bencode/encode.go      |  9 +++++++++
 bencode/encode_test.go | 11 +++++++++++

diff --git a/bencode/encode.go b/bencode/encode.go
index 57f0b80513189e957bfff416d18d93fce4b5f63e..8cbaf29f1f1435a8f4764c12ba794a0e8eb60e94 100644
--- a/bencode/encode.go
+++ b/bencode/encode.go
@@ -2,6 +2,7 @@ package bencode
 
 import (
 	"io"
+	"math/big"
 	"reflect"
 	"runtime"
 	"sort"
@@ -107,6 +108,14 @@
 func (e *Encoder) reflectValue(v reflect.Value) {
 
 	if e.reflectMarshaler(v) {
+		return
+	}
+
+	switch t := v.Interface().(type) {
+	case big.Int:
+		e.writeString("i")
+		e.writeString(t.String())
+		e.writeString("e")
 		return
 	}
 
diff --git a/bencode/encode_test.go b/bencode/encode_test.go
index a913a1c40427638a6ee9566cedf3afbd9c5237d3..bdb0d991a698e473465e6258a78b66cc6c120024 100644
--- a/bencode/encode_test.go
+++ b/bencode/encode_test.go
@@ -3,6 +3,7 @@
 import (
 	"bytes"
 	"fmt"
+	"math/big"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -68,6 +69,16 @@ 	}{nil}, "de"},
 	{struct {
 		A *string `bencode:",omitempty"`
 	}{new(string)}, "d1:A0:e"},
+	{bigIntFromString("62208002200000000000"), "i62208002200000000000e"},
+	{*bigIntFromString("62208002200000000000"), "i62208002200000000000e"},
+}
+
+func bigIntFromString(s string) *big.Int {
+	bi, ok := new(big.Int).SetString(s, 10)
+	if !ok {
+		panic(s)
+	}
+	return bi
 }
 
 func TestRandomEncode(t *testing.T) {