diff --git a/postgres-types/src/lib.rs b/postgres-types/src/lib.rs
index e912b378..8f758e97 100644
--- a/postgres-types/src/lib.rs
+++ b/postgres-types/src/lib.rs
@@ -868,6 +868,10 @@ where
         T::accepts(ty)
     }
 
+    fn encode_format(&self) -> Format {
+        (*self).encode_format()
+    }
+
     to_sql_checked!();
 }
 
@@ -887,6 +891,13 @@ impl<T: ToSql> ToSql for Option<T> {
         <T as ToSql>::accepts(ty)
     }
 
+    fn encode_format(&self) -> Format {
+        match self {
+            Some(ref val) => val.encode_format(),
+            None => Format::Binary,
+        }
+    }
+
     to_sql_checked!();
 }