diff --git a/address.go b/address.go
index f3612a4..b658e4a 100644
--- a/address.go
+++ b/address.go
@@ -5,7 +5,6 @@
 package btcutil
 
 import (
-	"bytes"
 	"encoding/hex"
 	"errors"
 
@@ -13,7 +12,7 @@ import (
 
 	"github.com/conformal/btcec"
 	"github.com/conformal/btcnet"
-	"github.com/conformal/btcwire"
+	"github.com/conformal/btcutil/base58"
 )
 
 var (
@@ -43,12 +42,7 @@ var (
 func encodeAddress(hash160 []byte, netID byte) string {
 	// Format is 1 byte for a network and address class (i.e. P2PKH vs
 	// P2SH), 20 bytes for a RIPEMD160 hash, and 4 bytes of checksum.
-	b := make([]byte, 0, 1+ripemd160.Size+4)
-	b = append(b, netID)
-	b = append(b, hash160...)
-	cksum := btcwire.DoubleSha256(b)[:4]
-	b = append(b, cksum...)
-	return Base58Encode(b)
+	return base58.CheckEncode(hash160[:ripemd160.Size], netID)
 }
 
 // Address is an interface type for any type of destination a transaction
@@ -99,21 +93,18 @@ func DecodeAddress(addr string, defaultNet *btcnet.Params) (Address, error) {
 	}
 
 	// Switch on decoded length to determine the type.
-	decoded := Base58Decode(addr)
-	switch len(decoded) {
-	case 1 + ripemd160.Size + 4: // P2PKH or P2SH
-		// Verify hash checksum.  Checksum is calculated as the first
-		// four bytes of double SHA256 of the network byte and hash.
-		tosum := decoded[:ripemd160.Size+1]
-		cksum := btcwire.DoubleSha256(tosum)[:4]
-		if !bytes.Equal(cksum, decoded[len(decoded)-4:]) {
+	decoded, netID, err := base58.CheckDecode(addr)
+	if err != nil {
+		if err == base58.ErrChecksum {
 			return nil, ErrChecksumMismatch
 		}
-
-		netID := decoded[0]
+		return nil, errors.New("decoded address is of unknown format")
+	}
+	switch len(decoded) {
+	case ripemd160.Size: // P2PKH or P2SH
 		isP2PKH := btcnet.IsPubKeyHashAddrID(netID)
 		isP2SH := btcnet.IsScriptHashAddrID(netID)
-		switch hash160 := decoded[1 : ripemd160.Size+1]; {
+		switch hash160 := decoded; {
 		case isP2PKH && isP2SH:
 			return nil, ErrAddressCollision
 		case isP2PKH:
diff --git a/base58.go b/base58.go
index a94d38a..ea21eb0 100644
--- a/base58.go
+++ b/base58.go
@@ -4,75 +4,16 @@
 
 package btcutil
 
-import (
-	"math/big"
-	"strings"
-)
+import "github.com/conformal/btcutil/base58"
 
-// alphabet is the modified base58 alphabet used by Bitcoin.
-const alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
-
-var bigRadix = big.NewInt(58)
-var bigZero = big.NewInt(0)
-
-// Base58Decode decodes a modified base58 string to a byte slice.
+// Base58Decode wraps the new base58 package for backwards compatibility.
+// TODO: Remove as soon as the other repos have been updated to use the new package.
 func Base58Decode(b string) []byte {
-	answer := big.NewInt(0)
-	j := big.NewInt(1)
-
-	for i := len(b) - 1; i >= 0; i-- {
-		tmp := strings.IndexAny(alphabet, string(b[i]))
-		if tmp == -1 {
-			return []byte("")
-		}
-		idx := big.NewInt(int64(tmp))
-		tmp1 := big.NewInt(0)
-		tmp1.Mul(j, idx)
-
-		answer.Add(answer, tmp1)
-		j.Mul(j, bigRadix)
-	}
-
-	tmpval := answer.Bytes()
-
-	var numZeros int
-	for numZeros = 0; numZeros < len(b); numZeros++ {
-		if b[numZeros] != alphabet[0] {
-			break
-		}
-	}
-	flen := numZeros + len(tmpval)
-	val := make([]byte, flen, flen)
-	copy(val[numZeros:], tmpval)
-
-	return val
+	return base58.Decode(b)
 }
 
-// Base58Encode encodes a byte slice to a modified base58 string.
+// Base58Encode wraps the new base58 package for backwards compatibility.
+// TODO: Remove as soon as the other repos have been updated to use the new package.
 func Base58Encode(b []byte) string {
-	x := new(big.Int)
-	x.SetBytes(b)
-
-	answer := make([]byte, 0, len(b)*136/100)
-	for x.Cmp(bigZero) > 0 {
-		mod := new(big.Int)
-		x.DivMod(x, bigRadix, mod)
-		answer = append(answer, alphabet[mod.Int64()])
-	}
-
-	// leading zero bytes
-	for _, i := range b {
-		if i != 0 {
-			break
-		}
-		answer = append(answer, alphabet[0])
-	}
-
-	// reverse
-	alen := len(answer)
-	for i := 0; i < alen/2; i++ {
-		answer[i], answer[alen-1-i] = answer[alen-1-i], answer[i]
-	}
-
-	return string(answer)
+	return base58.Encode(b)
 }
diff --git a/base58_test.go b/base58_test.go
deleted file mode 100644
index e80791a..0000000
--- a/base58_test.go
+++ /dev/null
@@ -1,98 +0,0 @@
-// Copyright (c) 2013-2014 Conformal Systems LLC.
-// Use of this source code is governed by an ISC
-// license that can be found in the LICENSE file.
-
-package btcutil_test
-
-import (
-	"bytes"
-	"encoding/hex"
-	"testing"
-
-	"github.com/conformal/btcutil"
-)
-
-var stringTests = []struct {
-	in  string
-	out string
-}{
-	{"", ""},
-	{" ", "Z"},
-	{"-", "n"},
-	{"0", "q"},
-	{"1", "r"},
-	{"-1", "4SU"},
-	{"11", "4k8"},
-	{"abc", "ZiCa"},
-	{"1234598760", "3mJr7AoUXx2Wqd"},
-	{"abcdefghijklmnopqrstuvwxyz", "3yxU3u1igY8WkgtjK92fbJQCd4BZiiT1v25f"},
-	{"00000000000000000000000000000000000000000000000000000000000000", "3sN2THZeE9Eh9eYrwkvZqNstbHGvrxSAM7gXUXvyFQP8XvQLUqNCS27icwUeDT7ckHm4FUHM2mTVh1vbLmk7y"},
-}
-
-var invalidStringTests = []struct {
-	in  string
-	out string
-}{
-	{"0", ""},
-	{"O", ""},
-	{"I", ""},
-	{"l", ""},
-	{"3mJr0", ""},
-	{"O3yxU", ""},
-	{"3sNI", ""},
-	{"4kl8", ""},
-	{"0OIl", ""},
-	{"!@#$%^&*()-_=+~`", ""},
-}
-
-var hexTests = []struct {
-	in  string
-	out string
-}{
-	{"61", "2g"},
-	{"626262", "a3gV"},
-	{"636363", "aPEr"},
-	{"73696d706c792061206c6f6e6720737472696e67", "2cFupjhnEsSn59qHXstmK2ffpLv2"},
-	{"00eb15231dfceb60925886b67d065299925915aeb172c06647", "1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L"},
-	{"516b6fcd0f", "ABnLTmg"},
-	{"bf4f89001e670274dd", "3SEo3LWLoPntC"},
-	{"572e4794", "3EFU7m"},
-	{"ecac89cad93923c02321", "EJDM8drfXA6uyA"},
-	{"10c8511e", "Rt5zm"},
-	{"00000000000000000000", "1111111111"},
-}
-
-func TestBase58(t *testing.T) {
-	// Base58Encode tests
-	for x, test := range stringTests {
-		tmp := []byte(test.in)
-		if res := btcutil.Base58Encode(tmp); res != test.out {
-			t.Errorf("Base58Encode test #%d failed: got: %s want: %s",
-				x, res, test.out)
-			continue
-		}
-	}
-
-	// Base58Decode tests
-	for x, test := range hexTests {
-		b, err := hex.DecodeString(test.in)
-		if err != nil {
-			t.Errorf("hex.DecodeString failed failed #%d: got: %s", x, test.in)
-			continue
-		}
-		if res := btcutil.Base58Decode(test.out); bytes.Equal(res, b) != true {
-			t.Errorf("Base58Decode test #%d failed: got: %q want: %q",
-				x, res, test.in)
-			continue
-		}
-	}
-
-	// Base58Decode with invalid input
-	for x, test := range invalidStringTests {
-		if res := btcutil.Base58Decode(test.in); string(res) != test.out {
-			t.Errorf("Base58Decode invalidString test #%d failed: got: %q want: %q",
-				x, res, test.out)
-			continue
-		}
-	}
-}
diff --git a/hdkeychain/extendedkey.go b/hdkeychain/extendedkey.go
index 01d3d49..d9ff8ce 100644
--- a/hdkeychain/extendedkey.go
+++ b/hdkeychain/extendedkey.go
@@ -21,6 +21,7 @@ import (
 	"github.com/conformal/btcec"
 	"github.com/conformal/btcnet"
 	"github.com/conformal/btcutil"
+	"github.com/conformal/btcutil/base58"
 	"github.com/conformal/btcwire"
 )
 
@@ -386,7 +387,7 @@ func (k *ExtendedKey) String() string {
 
 	checkSum := btcwire.DoubleSha256(serializedBytes)[:4]
 	serializedBytes = append(serializedBytes, checkSum...)
-	return btcutil.Base58Encode(serializedBytes)
+	return base58.Encode(serializedBytes)
 }
 
 // IsForNet returns whether or not the extended key is associated with the
@@ -473,7 +474,7 @@ func NewMaster(seed []byte) (*ExtendedKey, error) {
 func NewKeyFromString(key string) (*ExtendedKey, error) {
 	// The base58-decoded extended key must consist of a serialized payload
 	// plus an additional 4 bytes for the checksum.
-	decoded := btcutil.Base58Decode(key)
+	decoded := base58.Decode(key)
 	if len(decoded) != serializedKeyLen+4 {
 		return nil, ErrInvalidKeyLen
 	}
diff --git a/internal_test.go b/internal_test.go
index 702f0e8..b6f6903 100644
--- a/internal_test.go
+++ b/internal_test.go
@@ -15,6 +15,7 @@ import (
 	"golang.org/x/crypto/ripemd160"
 
 	"github.com/conformal/btcec"
+	"github.com/conformal/btcutil/base58"
 )
 
 // SetBlockBytes sets the internal serialized block byte buffer to the passed
@@ -68,6 +69,6 @@ func TstAddressPubKey(serializedPubKey []byte, pubKeyFormat PubKeyFormat,
 // TstAddressSAddr returns the expected script address bytes for
 // P2PKH and P2SH bitcoin addresses.
 func TstAddressSAddr(addr string) []byte {
-	decoded := Base58Decode(addr)
+	decoded := base58.Decode(addr)
 	return decoded[1 : 1+ripemd160.Size]
 }
diff --git a/wif.go b/wif.go
index c892be5..5fbf131 100644
--- a/wif.go
+++ b/wif.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/conformal/btcec"
 	"github.com/conformal/btcnet"
+	"github.com/conformal/btcutil/base58"
 	"github.com/conformal/btcwire"
 )
 
@@ -82,7 +83,7 @@ func (w *WIF) IsForNet(net *btcnet.Params) bool {
 // does not equal the expected value of 0x01.  ErrChecksumMismatch is returned
 // if the expected WIF checksum does not match the calculated checksum.
 func DecodeWIF(wif string) (*WIF, error) {
-	decoded := Base58Decode(wif)
+	decoded := base58.Decode(wif)
 	decodedLen := len(decoded)
 	var compress bool
 
@@ -143,7 +144,7 @@ func (w *WIF) String() string {
 	}
 	cksum := btcwire.DoubleSha256(a)[:4]
 	a = append(a, cksum...)
-	return Base58Encode(a)
+	return base58.Encode(a)
 }
 
 // SerializePubKey serializes the associated public key of the imported or