diff --git a/pgtype/array.go b/pgtype/array.go
index 29d6f803..54e85f37 100644
--- a/pgtype/array.go
+++ b/pgtype/array.go
@@ -19,7 +19,7 @@ import (
 
 type ArrayHeader struct {
 	ContainsNull bool
-	ElementOID   int32
+	ElementOID   uint32
 	Dimensions   []ArrayDimension
 }
 
@@ -55,7 +55,7 @@ func (dst *ArrayHeader) DecodeBinary(ci *ConnInfo, src []byte) (int, error) {
 	dst.ContainsNull = binary.BigEndian.Uint32(src[rp:]) == 1
 	rp += 4
 
-	dst.ElementOID = int32(binary.BigEndian.Uint32(src[rp:]))
+	dst.ElementOID = binary.BigEndian.Uint32(src[rp:])
 	rp += 4
 
 	if numDims > 0 {
@@ -84,7 +84,7 @@ func (src ArrayHeader) EncodeBinary(ci *ConnInfo, buf []byte) []byte {
 	}
 	buf = pgio.AppendInt32(buf, containsNull)
 
-	buf = pgio.AppendInt32(buf, src.ElementOID)
+	buf = pgio.AppendUint32(buf, src.ElementOID)
 
 	for i := range src.Dimensions {
 		buf = pgio.AppendInt32(buf, src.Dimensions[i].Length)
diff --git a/pgtype/array_codec.go b/pgtype/array_codec.go
index 4cc7e84c..922f6d26 100644
--- a/pgtype/array_codec.go
+++ b/pgtype/array_codec.go
@@ -155,7 +155,7 @@ func (p *encodePlanArrayCodecBinary) Encode(value interface{}, buf []byte) (newB
 
 	arrayHeader := ArrayHeader{
 		Dimensions: dimensions,
-		ElementOID: int32(p.ac.ElementOID),
+		ElementOID: p.ac.ElementOID,
 	}
 
 	containsNullIndex := len(buf) + 4