diff --git a/CHANGELOG.md b/CHANGELOG.md
index ffcc9594..a9d70ee0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+# Unreleased
+
+## Fixes
+
+* Oid underlying type changed to uint32, previously it was incorrectly int32
+
 # 2.9.0 (August 26, 2016)
 
 ## Fixes
diff --git a/messages.go b/messages.go
index 053a4c13..fec34dbb 100644
--- a/messages.go
+++ b/messages.go
@@ -53,6 +53,10 @@ func (s *startupMessage) Bytes() (buf []byte) {
 	return buf
 }
 
+// Oid (Object Identifier Type) is, according to https://www.postgresql.org/docs/current/static/datatype-oid.html,
+// used internally by PostgreSQL as a primary key for various system tables. It is currently implemented
+// as an unsigned four-byte integer. Its definition can be found in src/include/postgres_ext.h
+// in the PostgreSQL sources.
 type Oid uint32
 
 type FieldDescription struct {
@@ -140,7 +144,7 @@ func (wb *WriteBuf) WriteInt32(n int32) {
 
 func (wb *WriteBuf) WriteUint32(n uint32) {
 	b := make([]byte, 4)
-	binary.BigEndian.PutUint32(b, uint32(n))
+	binary.BigEndian.PutUint32(b, n)
 	wb.buf = append(wb.buf, b...)
 }
 
diff --git a/values.go b/values.go
index d2c56b92..e3486bed 100644
--- a/values.go
+++ b/values.go
@@ -1346,19 +1346,19 @@ func decodeInt4(vr *ValueReader) int32 {
 func decodeOid(vr *ValueReader) Oid {
 	if vr.Len() == -1 {
 		vr.Fatal(ProtocolError("Cannot decode null into Oid"))
-		return 0
+		return Oid(0)
 	}
 
 	if vr.Type().DataType != OidOid {
 		vr.Fatal(ProtocolError(fmt.Sprintf("Cannot decode oid %v into pgx.Oid", vr.Type().DataType)))
-		return 0
+		return Oid(0)
 	}
 
 	// Oid needs to decode text format because it is used in loadPgTypes
 	switch vr.Type().FormatCode {
 	case TextFormatCode:
 		s := vr.ReadString(vr.Len())
-		n, err := strconv.ParseInt(s, 10, 32)
+		n, err := strconv.ParseUint(s, 10, 32)
 		if err != nil {
 			vr.Fatal(ProtocolError(fmt.Sprintf("Received invalid Oid: %v", s)))
 		}
@@ -1366,7 +1366,7 @@ func decodeOid(vr *ValueReader) Oid {
 	case BinaryFormatCode:
 		if vr.Len() != 4 {
 			vr.Fatal(ProtocolError(fmt.Sprintf("Received an invalid size for an Oid: %d", vr.Len())))
-			return 0
+			return Oid(0)
 		}
 		return Oid(vr.ReadInt32())
 	default:
@@ -1381,7 +1381,7 @@ func encodeOid(w *WriteBuf, oid Oid, value Oid) error {
 	}
 
 	w.WriteInt32(4)
-	w.WriteInt32(int32(value))
+	w.WriteUint32(uint32(value))
 
 	return nil
 }