diff --git a/src/lib.rs b/src/lib.rs
index cb48b3c7fcd5..043f6f506d05 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -890,6 +890,12 @@ pub fn format_input<T: Write>(
 ) -> Result<(Summary, FileMap, FormatReport), (io::Error, Summary)> {
     let mut summary = Summary::default();
     if config.disable_all_formatting() {
+        // When the input is from stdin, echo back the input.
+        if let Input::Text(ref buf) = input {
+            if let Err(e) = io::stdout().write_all(buf.as_bytes()) {
+                return Err((e, summary));
+            }
+        }
         return Ok((summary, FileMap::new(), FormatReport::new()));
     }
     let codemap = Rc::new(CodeMap::new(FilePathMapping::empty()));
diff --git a/tests/config/disable_all_formatting.toml b/tests/config/disable_all_formatting.toml
new file mode 100644
index 000000000000..c7ad93bafe36
--- /dev/null
+++ b/tests/config/disable_all_formatting.toml
@@ -0,0 +1 @@
+disable_all_formatting = true
diff --git a/tests/system.rs b/tests/system.rs
index ce575f9f4923..44cfb732f4b4 100644
--- a/tests/system.rs
+++ b/tests/system.rs
@@ -14,8 +14,9 @@ extern crate term;
 
 use std::collections::HashMap;
 use std::fs;
-use std::io::{self, BufRead, BufReader, Read};
+use std::io::{self, BufRead, BufReader, Read, Write};
 use std::path::{Path, PathBuf};
+use std::process::{Command, Stdio};
 
 use rustfmt::*;
 use rustfmt::filemap::{write_system_newlines, FileMap};
@@ -157,6 +158,28 @@ fn stdin_formatting_smoke_test() {
     panic!("no stdin");
 }
 
+#[test]
+fn stdin_disable_all_formatting_test() {
+    let input = String::from("fn main() { println!(\"This should not be formatted.\"); }");
+    let mut child = Command::new("./target/debug/rustfmt")
+        .stdin(Stdio::piped())
+        .stdout(Stdio::piped())
+        .arg("--config-path=./tests/config/disable_all_formatting.toml")
+        .spawn()
+        .expect("failed to execute child");
+
+    {
+        let stdin = child.stdin.as_mut().expect("failed to get stdin");
+        stdin
+            .write_all(input.as_bytes())
+            .expect("failed to write stdin");
+    }
+    let output = child.wait_with_output().expect("failed to wait on child");
+    assert!(output.status.success());
+    assert!(output.stderr.is_empty());
+    assert_eq!(input, String::from_utf8(output.stdout).unwrap());
+}
+
 #[test]
 fn format_lines_errors_are_reported() {
     let long_identifier = String::from_utf8(vec![b'a'; 239]).unwrap();
diff --git a/tests/target/disable_all_formatting.rs b/tests/target/disable_all_formatting.rs
deleted file mode 100644
index ef7e4ee93626..000000000000
--- a/tests/target/disable_all_formatting.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-// rustfmt-disable_all_formatting: true
-// Don't format anything.
-
-fn main() { println!("This should not be formatted."); }