diff --git a/todoman/cli.py b/todoman/cli.py
index 774c4f40..ce7bef16 100644
--- a/todoman/cli.py
+++ b/todoman/cli.py
@@ -467,6 +467,30 @@ def done(ctx, todos):
         click.echo(ctx.formatter.detailed(todo))
 
 
+@cli.command()
+@pass_ctx
+@click.argument(
+    "todos",
+    nargs=-1,
+    required=True,
+    type=click.IntRange(0),
+    callback=_validate_todos,
+)
+# @catch_errors
+def undo(ctx, todos):
+    """Undo one or more tasks."""
+    toremove = []
+    for todo in todos:
+        removable = todo.undo()
+        if removable:
+            toremove.append(removable)
+        ctx.db.save(todo)
+        click.echo(ctx.formatter.detailed(todo))
+
+    for todo in toremove:
+        ctx.db.delete(todo)
+
+
 @cli.command()
 @pass_ctx
 @click.argument(
diff --git a/todoman/model.py b/todoman/model.py
index bb4044a3..a14a2448 100644
--- a/todoman/model.py
+++ b/todoman/model.py
@@ -252,6 +252,27 @@ def complete(self) -> None:
         self.percent_complete = 100
         self.status = "COMPLETED"
 
+    def undo(self) -> Todo | None:
+        """
+        Immediately restores this todo. Marks it as needs action, resets the
+        percentage to 0 and deletes the completed_at datetime.
+
+        If this todo belongs to a series, the one created at completion will
+        be deleted.
+
+        Returns the todo that will be deleted.
+        """
+        original = None
+        if self.is_recurring and self.related:
+            original = self.related.pop()
+            self.rrule = original.rrule
+
+        self.completed_at = None
+        self.percent_complete = 0
+        self.status = "NEEDS-ACTION"
+
+        return original
+
     @cached_property
     def path(self) -> str:
         if not self.list: