diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8e53c14f2..d8fbfe4c0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## 0.46 (unreleased)
 
+### Command Line Interface
+
+Removed the option `--missing-as-empty`. This is no longer needed as
+difftastic handles `/dev/null` gracefully on all platforms.
+
 ### Parsing
 
 Added support for Ada.
diff --git a/src/files.rs b/src/files.rs
index 9b92f0396..1aab69d71 100644
--- a/src/files.rs
+++ b/src/files.rs
@@ -3,7 +3,6 @@
 use std::io::Read;
 use std::{
     fs,
-    io::ErrorKind::*,
     path::{Path, PathBuf},
 };
 
@@ -13,11 +12,7 @@ use walkdir::WalkDir;
 use crate::exit_codes::EXIT_BAD_ARGUMENTS;
 use crate::options::FileArgument;
 
-pub fn read_files_or_die(
-    lhs_path: &FileArgument,
-    rhs_path: &FileArgument,
-    missing_as_empty: bool,
-) -> (Vec<u8>, Vec<u8>) {
+pub fn read_files_or_die(lhs_path: &FileArgument, rhs_path: &FileArgument) -> (Vec<u8>, Vec<u8>) {
     let lhs_res = read_file_arg(lhs_path);
     let rhs_res = read_file_arg(rhs_path);
 
@@ -25,12 +20,6 @@ pub fn read_files_or_die(
         // Both files exist, the happy case.
         (Ok(lhs_src), Ok(rhs_src)) => (lhs_src, rhs_src),
 
-        // Proceed if we've been given two paths and only one
-        // exists. This is important for mercurial diffs when a file
-        // has been removed.
-        (Ok(lhs_src), Err(e)) if missing_as_empty && e.kind() == NotFound => (lhs_src, vec![]),
-        (Err(e), Ok(rhs_src)) if missing_as_empty && e.kind() == NotFound => (vec![], rhs_src),
-
         (lhs_res, rhs_res) => {
             // Something else went wrong. Print both errors
             // encountered.
diff --git a/src/main.rs b/src/main.rs
index 1c8190532..518ea0a19 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -171,7 +171,6 @@ fn main() {
         Mode::Diff {
             diff_options,
             display_options,
-            missing_as_empty,
             set_exit_code,
             language_override,
             lhs_path,
@@ -238,7 +237,6 @@ fn main() {
                         &rhs_path,
                         &display_options,
                         &diff_options,
-                        missing_as_empty,
                         language_override,
                     );
                     print_diff_result(&display_options, &diff_result);
@@ -282,10 +280,9 @@ fn diff_file(
     rhs_path: &FileArgument,
     display_options: &DisplayOptions,
     diff_options: &DiffOptions,
-    missing_as_empty: bool,
     language_override: Option<parse::guess_language::Language>,
 ) -> DiffResult {
-    let (lhs_bytes, rhs_bytes) = read_files_or_die(lhs_path, rhs_path, missing_as_empty);
+    let (lhs_bytes, rhs_bytes) = read_files_or_die(lhs_path, rhs_path);
     diff_file_content(
         lhs_display_path,
         rhs_display_path,
@@ -621,7 +618,6 @@ fn diff_directories<'a>(
             &FileArgument::NamedPath(rhs_path),
             &display_options,
             &diff_options,
-            true,
             language_override,
         )
     })
diff --git a/src/options.rs b/src/options.rs
index b9d50e9f9..cf9d3b864 100644
--- a/src/options.rs
+++ b/src/options.rs
@@ -326,7 +326,6 @@ pub enum Mode {
     Diff {
         diff_options: DiffOptions,
         display_options: DisplayOptions,
-        missing_as_empty: bool,
         set_exit_code: bool,
         language_override: Option<guess_language::Language>,
         /// The path where we can read the LHS file. This is often a
@@ -518,10 +517,6 @@ pub fn parse_args() -> Mode {
 
     let print_unchanged = !matches.is_present("skip-unchanged");
 
-    // TODO: is this necessary now we handle /dev/null as an empty
-    // file on all platforms?
-    let missing_as_empty = matches.is_present("missing-as-empty");
-
     let set_exit_code = matches.is_present("exit-code");
 
     let check_only = matches.is_present("check-only");
@@ -549,7 +544,6 @@ pub fn parse_args() -> Mode {
     Mode::Diff {
         diff_options,
         display_options,
-        missing_as_empty,
         set_exit_code,
         language_override,
         lhs_path,