diff --git a/src/data.rs b/src/data.rs
index 3d1924a..8ffc8a4 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -66,9 +66,9 @@
 }
 
 impl Fields {
-    /// Get an iterator over the [`Field`] items in this object. This iterator
-    /// can be used to iterate over a named or unnamed struct or variant's
-    /// fields uniformly.
+    /// Get an iterator over the borrowed [`Field`] items in this object. This
+    /// iterator can be used to iterate over a named or unnamed struct or
+    /// variant's fields uniformly.
     ///
     /// [`Field`]: struct.Field.html
     pub fn iter(&self) -> punctuated::Iter<Field> {
@@ -78,6 +78,19 @@
             Fields::Unnamed(ref f) => f.unnamed.iter(),
         }
     }
+
+    /// Get an iterator over the mutably borrowed [`Field`] items in this
+    /// object. This iterator can be used to iterate over a named or unnamed
+    /// struct or variant's fields uniformly.
+    ///
+    /// [`Field`]: struct.Field.html
+    pub fn iter_mut(&mut self) -> punctuated::IterMut<Field> {
+        match *self {
+            Fields::Unit => punctuated::IterMut::private_empty(),
+            Fields::Named(ref mut f) => f.named.iter_mut(),
+            Fields::Unnamed(ref mut f) => f.unnamed.iter_mut(),
+        }
+    }
 }
 
 impl<'a> IntoIterator for &'a Fields {
@@ -89,6 +102,15 @@
     }
 }
 
+impl<'a> IntoIterator for &'a mut Fields {
+    type Item = &'a mut Field;
+    type IntoIter = punctuated::IterMut<'a, Field>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter_mut()
+    }
+}
+
 ast_struct! {
     /// A field of a struct or enum variant.
     ///
diff --git a/src/punctuated.rs b/src/punctuated.rs
index 0ab23fc..b4a0b3f 100644
--- a/src/punctuated.rs
+++ b/src/punctuated.rs
@@ -521,6 +521,17 @@
     last: option::IntoIter<&'a mut T>,
 }
 
+#[cfg(any(feature = "full", feature = "derive"))]
+impl<'a, T> IterMut<'a, T> {
+    // Not public API.
+    #[doc(hidden)]
+    pub fn private_empty() -> Self {
+        IterMut {
+            inner: Box::new(iter::empty()),
+        }
+    }
+}
+
 impl<'a, T> Iterator for IterMut<'a, T> {
     type Item = &'a mut T;