diff --git a/Cargo.lock b/Cargo.lock
index 13420f4..73c80f8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -157,6 +157,22 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "edit"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3cdd6936f8bd9782e28932eef853bfcd8548992ce5748bb3e7e88bad613d0ee0"
+dependencies = [
+ "tempfile",
+ "which",
+]
+
+[[package]]
+name = "either"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
+
 [[package]]
 name = "fake-simd"
 version = "0.1.2"
@@ -287,6 +303,12 @@ dependencies = [
  "sha-1",
 ]
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -329,6 +351,46 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+ "rand_hc",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.2.10"
@@ -348,6 +410,15 @@ dependencies = [
  "redox_syscall",
 ]
 
+[[package]]
+name = "remove_dir_all"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3acd125665422973a33ac9d3dd2df85edad0f4ae9b00dafb1a05e43a9f5ef8e7"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "sha-1"
 version = "0.8.2"
@@ -401,6 +472,20 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "tempfile"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dac1c663cfc93810f88aed9b8941d48cabf856a1b111c29a40439018d870eb22"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "rand",
+ "redox_syscall",
+ "remove_dir_all",
+ "winapi",
+]
+
 [[package]]
 name = "termcolor"
 version = "1.1.2"
@@ -459,6 +544,7 @@ dependencies = [
  "colored",
  "computus",
  "directories",
+ "edit",
  "pest",
  "pest_derive",
  "structopt",
@@ -524,6 +610,17 @@ version = "0.10.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
 
+[[package]]
+name = "which"
+version = "4.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea187a8ef279bc014ec368c27a920da2024d2a711109bfbe3440585d5cf27ad9"
+dependencies = [
+ "either",
+ "lazy_static",
+ "libc",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
diff --git a/Cargo.toml b/Cargo.toml
index 458483b..2807701 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ codespan-reporting = "0.11.1"
 colored = "2.0.0"
 computus = "1.0.0"
 directories = "4.0.1"
+edit = "0.1.3"
 pest = "2.1.3"
 pest_derive = "2.1.0"
 structopt = "0.3.25"
diff --git a/src/cli.rs b/src/cli.rs
index 5baf98c..4bb98ac 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -8,7 +8,7 @@ use directories::ProjectDirs;
 use structopt::StructOpt;
 
 use crate::eval::{self, DateRange, Entry, EntryMode};
-use crate::files::arguments::{CliIdent, CliRange};
+use crate::files::arguments::{CliDate, CliIdent, CliRange};
 use crate::files::{self, FileSource, Files, ParseError};
 
 use self::error::Error;
@@ -18,6 +18,7 @@ mod cancel;
 mod done;
 mod error;
 mod layout;
+mod log;
 mod print;
 mod show;
 
@@ -57,6 +58,11 @@ pub enum Command {
         #[structopt(required = true)]
         entries: Vec<usize>,
     },
+    /// Edits or creates a log entry
+    Log {
+        #[structopt(default_value = "today")]
+        date: String,
+    },
     /// Reformats all loaded files
     Fmt,
 }
@@ -162,6 +168,12 @@ fn run_command(
             let layout = find_layout(files, &entries, range, now);
             print::print(&layout);
         }
+        Some(Command::Log { date }) => {
+            match parse_eval_arg("date", date, |date: CliDate| date.eval((), now.date())) {
+                Some(date) => log::log(files, date)?,
+                None => process::exit(1),
+            };
+        }
         Some(Command::Fmt) => files.mark_all_dirty(),
     }
     Ok(())
diff --git a/src/cli/error.rs b/src/cli/error.rs
index 7ad1b01..b4246c3 100644
--- a/src/cli/error.rs
+++ b/src/cli/error.rs
@@ -1,3 +1,5 @@
+use std::io;
+
 use chrono::NaiveDate;
 use codespan_reporting::files::Files;
 use codespan_reporting::term::Config;
@@ -15,6 +17,8 @@ pub enum Error<S> {
     NoSuchLog(NaiveDate),
     #[error("Not a task")]
     NotATask(Vec<usize>),
+    #[error("Error editing log for {date}: {error}")]
+    EditingLog { date: NaiveDate, error: io::Error },
 }
 
 impl<'a, F: Files<'a>> Eprint<'a, F> for Error<F::FileId> {
@@ -33,6 +37,10 @@ impl<'a, F: Files<'a>> Eprint<'a, F> for Error<F::FileId> {
                     eprintln!("{} are not tasks.", ns.join(", "));
                 }
             }
+            Error::EditingLog { date, error } => {
+                eprintln!("Error editing log for {}", date);
+                eprintln!("  {}", error);
+            }
         }
     }
 }
diff --git a/src/cli/log.rs b/src/cli/log.rs
new file mode 100644
index 0000000..6456827
--- /dev/null
+++ b/src/cli/log.rs
@@ -0,0 +1,26 @@
+use chrono::NaiveDate;
+
+use crate::files::Files;
+
+use super::error::Error;
+
+pub fn log<S>(files: &mut Files, date: NaiveDate) -> Result<(), Error<S>> {
+    let desc = files
+        .log(date)
+        .map(|log| log.value.desc.join("\n"))
+        .unwrap_or_default();
+
+    let mut builder = edit::Builder::new();
+    builder.suffix(".md");
+    let edited = edit::edit_with_builder(desc, &builder)
+        .map_err(|error| Error::EditingLog { date, error })?;
+
+    let edited = edited
+        .lines()
+        .map(|line| line.to_string())
+        .collect::<Vec<_>>();
+
+    files.set_log(date, edited);
+
+    Ok(())
+}
diff --git a/src/files.rs b/src/files.rs
index 3f32812..007ad63 100644
--- a/src/files.rs
+++ b/src/files.rs
@@ -339,6 +339,21 @@ impl Files {
         }
     }
 
+    fn latest_log(&self) -> Option<(NaiveDate, Source)> {
+        self.logs
+            .iter()
+            .map(|(d, s)| (*d, *s))
+            .max_by_key(|(d, _)| *d)
+    }
+
+    fn latest_log_before(&self, date: NaiveDate) -> Option<(NaiveDate, Source)> {
+        self.logs
+            .iter()
+            .map(|(d, s)| (*d, *s))
+            .filter(|(d, _)| d <= &date)
+            .max_by_key(|(d, _)| *d)
+    }
+
     pub fn now(&self) -> DateTime<&Tz> {
         if let Some(tz) = &self.timezone {
             Utc::now().with_timezone(&tz)
@@ -355,6 +370,18 @@ impl Files {
         }
     }
 
+    fn modify(&mut self, source: Source, edit: impl FnOnce(&mut Command)) {
+        let file = &mut self.files[source.file];
+        edit(&mut file.file.commands[source.command]);
+        file.dirty = true;
+    }
+
+    fn insert(&mut self, file: FileSource, command: Command) {
+        let file = &mut self.files[file.0];
+        file.file.commands.push(command);
+        file.dirty = true;
+    }
+
     /// Add a [`Done`] statement to the task identified by `source`.
     ///
     /// Returns whether the addition was successful. It can fail if the entry
@@ -370,6 +397,26 @@ impl Files {
         true
     }
 
+    pub fn set_log(&mut self, date: NaiveDate, desc: Vec<String>) {
+        if let Some(source) = self.logs.get(&date).cloned() {
+            self.modify(source, |command| match command {
+                Command::Log(log) => log.desc = desc,
+                _ => unreachable!(),
+            });
+        } else {
+            let file = self
+                .latest_log_before(date)
+                .or_else(|| self.latest_log())
+                .map(|(_, source)| source.file())
+                .unwrap_or(FileSource(0));
+
+            let date = Spanned::dummy(date);
+            let command = Command::Log(Log { date, desc });
+
+            self.insert(file, command);
+        }
+    }
+
     /* Errors */
 
     fn cs_id(&self, file: FileSource) -> usize {
diff --git a/src/files/arguments.rs b/src/files/arguments.rs
index 6ff4b7d..100e7f1 100644
--- a/src/files/arguments.rs
+++ b/src/files/arguments.rs
@@ -46,6 +46,19 @@ fn parse_cli_date(p: Pair<'_, Rule>) -> Result<CliDate> {
     Ok(CliDate { datum, delta })
 }
 
+impl FromStr for CliDate {
+    type Err = ParseError<()>;
+
+    fn from_str(s: &str) -> result::Result<Self, ParseError<()>> {
+        let mut pairs =
+            TodayfileParser::parse(Rule::cli_date, s).map_err(|e| ParseError::new((), e))?;
+        let p = pairs.next().unwrap();
+        assert_eq!(pairs.next(), None);
+
+        parse_cli_date(p).map_err(|e| ParseError::new((), e))
+    }
+}
+
 #[derive(Debug)]
 pub enum CliIdent {
     Number(usize),
diff --git a/src/files/primitives.rs b/src/files/primitives.rs
index 118bfb3..e63b867 100644
--- a/src/files/primitives.rs
+++ b/src/files/primitives.rs
@@ -31,6 +31,10 @@ impl Span {
             end: cmp::max(self.end, other.end),
         }
     }
+
+    fn dummy() -> Self {
+        Self { start: 0, end: 0 }
+    }
 }
 
 #[derive(Clone, Copy)]
@@ -49,6 +53,10 @@ impl<T> Spanned<T> {
     pub fn new(span: Span, value: T) -> Self {
         Self { span, value }
     }
+
+    pub fn dummy(value: T) -> Self {
+        Self::new(Span::dummy(), value)
+    }
 }
 
 // I don't know how one would write this. It works as a polymorphic standalone