diff --git a/serde_macros/src/de.rs b/serde_macros/src/de.rs
index 35853243..7b455f61 100644
--- a/serde_macros/src/de.rs
+++ b/serde_macros/src/de.rs
@@ -616,7 +616,7 @@ fn deserialize_field_visitor(
             .collect();
 
         quote_expr!(cx,
-                    match D::fmt() {
+                    match D::format() {
                         $fmt_matches,
                         _ => match value {
                             $default_field_arms,
diff --git a/serde_macros/src/ser.rs b/serde_macros/src/ser.rs
index be0896d7..24c35806 100644
--- a/serde_macros/src/ser.rs
+++ b/serde_macros/src/ser.rs
@@ -533,7 +533,7 @@ fn serialize_struct_visitor<I>(
                         .collect::<Vec<_>>();
                     quote_expr!(cx,
                         {
-                            match S::fmt() {
+                            match S::format() {
                                 $arms,
                                 _ => $default
                             }
diff --git a/src/de/mod.rs b/src/de/mod.rs
index 091adbc6..260cba90 100644
--- a/src/de/mod.rs
+++ b/src/de/mod.rs
@@ -114,7 +114,7 @@ pub trait Deserializer {
         self.visit(visitor)
     }
 
-    fn fmt() -> &'static str {
+    fn format() -> &'static str {
         ""
     }
 }
diff --git a/src/json/de.rs b/src/json/de.rs
index dde68ed2..e838ec75 100644
--- a/src/json/de.rs
+++ b/src/json/de.rs
@@ -465,7 +465,7 @@ impl<Iter> de::Deserializer for Deserializer<Iter>
     }
 
     #[inline]
-    fn fmt() -> &'static str {
+    fn format() -> &'static str {
         "json"
     }
 }
diff --git a/src/json/ser.rs b/src/json/ser.rs
index 5537859e..deaace30 100644
--- a/src/json/ser.rs
+++ b/src/json/ser.rs
@@ -258,7 +258,7 @@ impl<W, F> ser::Serializer for Serializer<W, F>
     }
 
     #[inline]
-    fn fmt() -> &'static str {
+    fn format() -> &'static str {
         "json"
     }
 }
diff --git a/src/json/value.rs b/src/json/value.rs
index c9b8afc0..68e58ae5 100644
--- a/src/json/value.rs
+++ b/src/json/value.rs
@@ -573,7 +573,7 @@ impl ser::Serializer for Serializer {
     }
 
     #[inline]
-    fn fmt() -> &'static str {
+    fn format() -> &'static str {
         "value"
     }
 }
@@ -684,7 +684,7 @@ impl de::Deserializer for Deserializer {
     }
 
     #[inline]
-    fn fmt() -> &'static str {
+    fn format() -> &'static str {
         "value"
     }
 }
diff --git a/src/ser/mod.rs b/src/ser/mod.rs
index 432d2535..612ff059 100644
--- a/src/ser/mod.rs
+++ b/src/ser/mod.rs
@@ -180,7 +180,7 @@ pub trait Serializer {
         where K: Serialize,
               V: Serialize;
 
-    fn fmt() -> &'static str {
+    fn format() -> &'static str {
         ""
     }
 }