diff --git a/authentication.go b/authentication.go
index bc654c4f..5ff05d96 100644
--- a/authentication.go
+++ b/authentication.go
@@ -3,9 +3,9 @@ package pgproto3
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 
 	"github.com/jackc/pgio"
-	"github.com/pkg/errors"
 )
 
 // Authentication message type constants.
@@ -60,7 +60,7 @@ func (dst *Authentication) Decode(src []byte) error {
 	case AuthTypeSASLContinue, AuthTypeSASLFinal:
 		dst.SASLData = src[4:]
 	default:
-		return errors.Errorf("unknown authentication type: %d", dst.Type)
+		return fmt.Errorf("unknown authentication type: %d", dst.Type)
 	}
 
 	return nil
diff --git a/backend.go b/backend.go
index be8f3bdb..176a25ba 100644
--- a/backend.go
+++ b/backend.go
@@ -4,8 +4,6 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io"
-
-	"github.com/pkg/errors"
 )
 
 // Backend acts as a server for the PostgreSQL wire protocol version 3.
@@ -124,7 +122,7 @@ func (b *Backend) Receive() (FrontendMessage, error) {
 	case 'X':
 		msg = &b.terminate
 	default:
-		return nil, errors.Errorf("unknown message type: %c", b.msgType)
+		return nil, fmt.Errorf("unknown message type: %c", b.msgType)
 	}
 
 	msgBody, err := b.cr.Next(b.bodyLen)
diff --git a/cancel_request.go b/cancel_request.go
index ec1d8606..942e404b 100644
--- a/cancel_request.go
+++ b/cancel_request.go
@@ -3,9 +3,9 @@ package pgproto3
 import (
 	"encoding/binary"
 	"encoding/json"
+	"errors"
 
 	"github.com/jackc/pgio"
-	"github.com/pkg/errors"
 )
 
 const cancelRequestCode = 80877102
@@ -20,13 +20,13 @@ func (*CancelRequest) Frontend() {}
 
 func (dst *CancelRequest) Decode(src []byte) error {
 	if len(src) != 12 {
-		return errors.Errorf("bad cancel request size")
+		return errors.New("bad cancel request size")
 	}
 
 	requestCode := binary.BigEndian.Uint32(src)
 
 	if requestCode != cancelRequestCode {
-		return errors.Errorf("bad cancel request code")
+		return errors.New("bad cancel request code")
 	}
 
 	dst.ProcessID = binary.BigEndian.Uint32(src[4:])
diff --git a/frontend.go b/frontend.go
index bcf796e1..f6ebaf43 100644
--- a/frontend.go
+++ b/frontend.go
@@ -2,9 +2,8 @@ package pgproto3
 
 import (
 	"encoding/binary"
+	"fmt"
 	"io"
-
-	"github.com/pkg/errors"
 )
 
 // Frontend acts as a client for the PostgreSQL wire protocol version 3.
@@ -115,7 +114,7 @@ func (b *Frontend) Receive() (BackendMessage, error) {
 	case 'Z':
 		msg = &b.readyForQuery
 	default:
-		return nil, errors.Errorf("unknown message type: %c", b.msgType)
+		return nil, fmt.Errorf("unknown message type: %c", b.msgType)
 	}
 
 	msgBody, err := b.cr.Next(b.bodyLen)
diff --git a/frontend_test.go b/frontend_test.go
index 2d5c8de7..1d6a07ae 100644
--- a/frontend_test.go
+++ b/frontend_test.go
@@ -1,10 +1,9 @@
 package pgproto3_test
 
 import (
+	"errors"
 	"testing"
 
-	"github.com/pkg/errors"
-
 	"github.com/jackc/pgproto3/v2"
 )
 
diff --git a/go.mod b/go.mod
index 800f6043..4821676a 100644
--- a/go.mod
+++ b/go.mod
@@ -3,8 +3,6 @@ module github.com/jackc/pgproto3/v2
 go 1.12
 
 require (
-	github.com/jackc/chunkreader v1.0.0
 	github.com/jackc/chunkreader/v2 v2.0.0
 	github.com/jackc/pgio v1.0.0
-	github.com/pkg/errors v0.8.1
 )
diff --git a/go.sum b/go.sum
index 5dd456ad..36160794 100644
--- a/go.sum
+++ b/go.sum
@@ -1,8 +1,4 @@
-github.com/jackc/chunkreader v1.0.0 h1:4s39bBR8ByfqH+DKm8rQA3E1LHZWB9XWcrz8fqaZbe0=
-github.com/jackc/chunkreader v1.0.0/go.mod h1:RT6O25fNZIuasFJRyZ4R/Y2BbhasbmZXF9QQ7T3kePo=
 github.com/jackc/chunkreader/v2 v2.0.0 h1:DUwgMQuuPnS0rhMXenUtZpqZqrR/30NWY+qQvTpSvEs=
 github.com/jackc/chunkreader/v2 v2.0.0/go.mod h1:odVSm741yZoC3dpHEUXIqA9tQRhFrgOHwnPIn9lDKlk=
 github.com/jackc/pgio v1.0.0 h1:g12B9UwVnzGhueNavwioyEEpAmqMe1E/BN9ES+8ovkE=
 github.com/jackc/pgio v1.0.0/go.mod h1:oP+2QK2wFfUWgr+gxjoBH9KGBb31Eio69xUb0w5bYf8=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
-github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
diff --git a/ssl_request.go b/ssl_request.go
index 2f4b378a..96ce489e 100644
--- a/ssl_request.go
+++ b/ssl_request.go
@@ -3,9 +3,9 @@ package pgproto3
 import (
 	"encoding/binary"
 	"encoding/json"
+	"errors"
 
 	"github.com/jackc/pgio"
-	"github.com/pkg/errors"
 )
 
 const sslRequestNumber = 80877103
@@ -18,13 +18,13 @@ func (*SSLRequest) Frontend() {}
 
 func (dst *SSLRequest) Decode(src []byte) error {
 	if len(src) < 4 {
-		return errors.Errorf("ssl request too short")
+		return errors.New("ssl request too short")
 	}
 
 	requestCode := binary.BigEndian.Uint32(src)
 
 	if requestCode != sslRequestNumber {
-		return errors.Errorf("bad ssl request code")
+		return errors.New("bad ssl request code")
 	}
 
 	return nil
diff --git a/startup_message.go b/startup_message.go
index 5be42500..5f1cd24f 100644
--- a/startup_message.go
+++ b/startup_message.go
@@ -4,9 +4,10 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+	"errors"
+	"fmt"
 
 	"github.com/jackc/pgio"
-	"github.com/pkg/errors"
 )
 
 const ProtocolVersionNumber = 196608 // 3.0
@@ -23,14 +24,14 @@ func (*StartupMessage) Frontend() {}
 // type identifier and 4 byte message length.
 func (dst *StartupMessage) Decode(src []byte) error {
 	if len(src) < 4 {
-		return errors.Errorf("startup message too short")
+		return errors.New("startup message too short")
 	}
 
 	dst.ProtocolVersion = binary.BigEndian.Uint32(src)
 	rp := 4
 
 	if dst.ProtocolVersion != ProtocolVersionNumber {
-		return errors.Errorf("Bad startup message version number. Expected %d, got %d", ProtocolVersionNumber, dst.ProtocolVersion)
+		return fmt.Errorf("Bad startup message version number. Expected %d, got %d", ProtocolVersionNumber, dst.ProtocolVersion)
 	}
 
 	dst.Parameters = make(map[string]string)
@@ -53,7 +54,7 @@ func (dst *StartupMessage) Decode(src []byte) error {
 
 		if len(src[rp:]) == 1 {
 			if src[rp] != 0 {
-				return errors.Errorf("Bad startup message last byte. Expected 0, got %d", src[rp])
+				return fmt.Errorf("Bad startup message last byte. Expected 0, got %d", src[rp])
 			}
 			break
 		}