diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 1.6.3
+
+- Added `unknownEnum` encoder
+
 # 1.6.2
 
 - Added composite encoder
diff --git a/hasql.cabal b/hasql.cabal
--- a/hasql.cabal
+++ b/hasql.cabal
@@ -1,5 +1,5 @@
 name: hasql
-version: 1.6.2
+version: 1.6.3
 category: Hasql, Database, PostgreSQL
 synopsis: An efficient PostgreSQL driver with a flexible mapping API
 description:
diff --git a/library/Hasql/Encoders.hs b/library/Hasql/Encoders.hs
--- a/library/Hasql/Encoders.hs
+++ b/library/Hasql/Encoders.hs
@@ -43,6 +43,7 @@
     name,
     oid,
     enum,
+    unknownEnum,
     unknown,
     array,
     foldableArray,
diff --git a/library/Hasql/Private/Encoders.hs b/library/Hasql/Private/Encoders.hs
--- a/library/Hasql/Private/Encoders.hs
+++ b/library/Hasql/Private/Encoders.hs
@@ -269,6 +269,16 @@
 enum mapping = Value (Value.unsafePTI PTI.text (const (A.text_strict . mapping)) (C.text . mapping))
 
 -- |
+-- Variation of 'enum' with unknown OID.
+-- This function does not identify the type to Postgres,
+-- so Postgres must be able to derive the type from context.
+-- When you find yourself in such situation just provide an explicit type in the query
+-- using the :: operator.
+{-# INLINEABLE unknownEnum #-}
+unknownEnum :: (a -> Text) -> Value a
+unknownEnum mapping = Value (Value.unsafePTI PTI.binaryUnknown (const (A.text_strict . mapping)) (C.text . mapping))
+
+-- |
 -- Identifies the value with the PostgreSQL's \"unknown\" type,
 -- thus leaving it up to Postgres to infer the actual type of the value.
 --
diff --git a/tasty/Main.hs b/tasty/Main.hs
--- a/tasty/Main.hs
+++ b/tasty/Main.hs
@@ -127,6 +127,34 @@
            in do
                 x <- Connection.with (Session.run session)
                 assertEqual (show x) (Right (Right ((1, True), ("hello", 3)))) x,
+        testGroup "unknownEnum" $
+          [ testCase "" $ do
+              res <- DSL.session $ do
+                let statement =
+                      Statement.Statement sql mempty Decoders.noResult True
+                      where
+                        sql =
+                          "drop type if exists mood"
+                 in DSL.statement () statement
+                let statement =
+                      Statement.Statement sql mempty Decoders.noResult True
+                      where
+                        sql =
+                          "create type mood as enum ('sad', 'ok', 'happy')"
+                 in DSL.statement () statement
+                let statement =
+                      Statement.Statement sql encoder decoder True
+                      where
+                        sql =
+                          "select $1"
+                        decoder =
+                          (Decoders.singleRow ((Decoders.column . Decoders.nonNullable) (Decoders.enum (Just . id))))
+                        encoder =
+                          Encoders.param (Encoders.nonNullable (Encoders.unknownEnum id))
+                 in DSL.statement "ok" statement
+
+              assertEqual "" (Right "ok") res
+          ],
         testCase "Composite encoding" $ do
           let value =
                 (123, 456, 789, "abc")