diff --git a/consensus/types/proposal.go b/consensus/types/proposal.go
index 79a3f001..c9dbad1a 100644
--- a/consensus/types/proposal.go
+++ b/consensus/types/proposal.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/tendermint/tendermint/account"
 	"github.com/tendermint/tendermint/binary"
+	. "github.com/tendermint/tendermint/common"
 	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/types"
 )
@@ -39,9 +40,11 @@ func (p *Proposal) String() string {
 }
 
 func (p *Proposal) WriteSignBytes(w io.Writer, n *int64, err *error) {
-	binary.WriteString(config.App().GetString("Network"), w, n, err)
-	binary.WriteUvarint(p.Height, w, n, err)
-	binary.WriteUvarint(p.Round, w, n, err)
-	binary.WriteBinary(p.BlockParts, w, n, err)
-	binary.WriteBinary(p.POLParts, w, n, err)
+	// We hex encode the network name so we don't deal with escaping issues.
+	binary.WriteTo([]byte(Fmt(`{"Network":"%X"`, config.App().GetString("Network"))), w, n, err)
+	binary.WriteTo([]byte(`,"Proprosal":{"BlockParts":`), w, n, err)
+	p.BlockParts.WriteSignBytes(w, n, err)
+	binary.WriteTo([]byte(Fmt(`,"Height":%v,"POLParts":`, p.Height)), w, n, err)
+	p.POLParts.WriteSignBytes(w, n, err)
+	binary.WriteTo([]byte(Fmt(`,"Round":%v}}`, p.Round)), w, n, err)
 }
diff --git a/consensus/types/proposal_test.go b/consensus/types/proposal_test.go
new file mode 100644
index 00000000..6db16474
--- /dev/null
+++ b/consensus/types/proposal_test.go
@@ -0,0 +1,27 @@
+package consensus
+
+import (
+	"testing"
+
+	"github.com/tendermint/tendermint/account"
+	. "github.com/tendermint/tendermint/common"
+	"github.com/tendermint/tendermint/config"
+	"github.com/tendermint/tendermint/types"
+)
+
+func TestProposalSignable(t *testing.T) {
+	proposal := &Proposal{
+		Height:     12345,
+		Round:      23456,
+		BlockParts: types.PartSetHeader{111, []byte("blockparts")},
+		POLParts:   types.PartSetHeader{222, []byte("polparts")},
+		Signature:  nil,
+	}
+	signBytes := account.SignBytes(proposal)
+	signStr := string(signBytes)
+	expected := Fmt(`{"Network":"%X","Proprosal":{"BlockParts":{"Hash":"626C6F636B7061727473","Total":111},"Height":12345,"POLParts":{"Hash":"706F6C7061727473","Total":222},"Round":23456}}`,
+		config.App().GetString("Network"))
+	if signStr != expected {
+		t.Errorf("Got unexpected sign string for SendTx. Expected:\n%v\nGot:\n%v", expected, signStr)
+	}
+}
diff --git a/types/part_set.go b/types/part_set.go
index d403809d..1251ea5d 100644
--- a/types/part_set.go
+++ b/types/part_set.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/tendermint/tendermint/binary"
 	. "github.com/tendermint/tendermint/common"
 	"github.com/tendermint/tendermint/merkle"
 )
@@ -84,6 +85,10 @@ func (psh PartSetHeader) Equals(other PartSetHeader) bool {
 	return psh.Total == other.Total && bytes.Equal(psh.Hash, other.Hash)
 }
 
+func (psh PartSetHeader) WriteSignBytes(w io.Writer, n *int64, err *error) {
+	binary.WriteTo([]byte(Fmt(`{"Hash":"%X","Total":%v}`, psh.Hash, psh.Total)), w, n, err)
+}
+
 //-------------------------------------
 
 type PartSet struct {