diff --git a/src/HyperLogLog.h b/src/HyperLogLog.h
index 81c19067a1..34a2afd9b7 100644
--- a/src/HyperLogLog.h
+++ b/src/HyperLogLog.h
@@ -10,7 +10,10 @@
  */
 #define conf .95
 
+class CardinalityVal;
+
 class CardinalityCounter {
+ friend class CardinalityVal;
 
  private:
   /*
diff --git a/src/OpaqueVal.cc b/src/OpaqueVal.cc
index 604ce2938e..d1d97c1f8c 100644
--- a/src/OpaqueVal.cc
+++ b/src/OpaqueVal.cc
@@ -1,9 +1,10 @@
 #include "OpaqueVal.h"
 #include "Reporter.h"
 #include "Serializer.h"
+#include "HyperLogLog.h"
 
 
-CardinalityVal::CardinalityVal() 
+CardinalityVal::CardinalityVal() : OpaqueVal(new OpaqueType("cardinality"))
 	{
 	valid = false;
 	}
@@ -14,6 +15,49 @@ CardinalityVal::~CardinalityVal()
 		delete c;
 	}
 
+IMPLEMENT_SERIAL(CardinalityVal, SER_CARDINALITY_VAL);
+
+bool CardinalityVal::DoSerialize(SerialInfo* info) const
+	{
+	DO_SERIALIZE(SER_CARDINALITY_VAL, OpaqueVal);
+
+	if ( ! IsValid() )
+		return true;
+
+	assert(c);
+
+	bool valid = true;
+
+	valid &= SERIALIZE(c->m);
+	for ( int i = 0; i < c->m; i++ ) 
+		{
+		valid &= SERIALIZE(c->buckets[i]);
+		}
+
+	return valid;
+	}
+
+bool CardinalityVal::DoUnserialize(UnserialInfo* info)
+	{
+	DO_UNSERIALIZE(OpaqueVal);
+
+	if ( ! IsValid() )
+		return true;
+
+	uint64_t m;
+	bool valid = UNSERIALIZE(&m);
+
+	c = new CardinalityCounter(m);
+	uint8_t* buckets = c->buckets;
+	for ( int i = 0; i < m; i++ ) 
+		{
+		uint8_t* currbucket = buckets + i;
+		valid &= UNSERIALIZE( currbucket );
+		}
+
+	return valid;
+	}
+
 bool CardinalityVal::Init(CardinalityCounter* arg_c)
 	{
 	if ( valid )
diff --git a/src/OpaqueVal.h b/src/OpaqueVal.h
index 01f86529c7..1bdd842cad 100644
--- a/src/OpaqueVal.h
+++ b/src/OpaqueVal.h
@@ -11,17 +11,17 @@ class CardinalityCounter;
 
 class CardinalityVal: public OpaqueVal {
 public:
-	CardinalityVal();
-	~CardinalityVal();
 	bool Init(CardinalityCounter*);
 	bool IsValid() const { return valid; };
 	CardinalityCounter* Get() { return c; };
+	CardinalityVal();
+	~CardinalityVal();
 
 private:
 	bool valid;
 	CardinalityCounter* c;
 
-//	DECLARE_SERIAL(CardinalityVal); Fixme?
+	DECLARE_SERIAL(CardinalityVal); 
 };
 
 
diff --git a/src/SerialTypes.h b/src/SerialTypes.h
index 723badab1e..56a1c5e8dd 100644
--- a/src/SerialTypes.h
+++ b/src/SerialTypes.h
@@ -104,6 +104,7 @@ SERIAL_VAL(MD5_VAL, 16)
 SERIAL_VAL(SHA1_VAL, 17)
 SERIAL_VAL(SHA256_VAL, 18)
 SERIAL_VAL(ENTROPY_VAL, 19)
+SERIAL_VAL(CARDINALITY_VAL, 20)
 
 #define SERIAL_EXPR(name, val) SERIAL_CONST(name, val, EXPR)
 SERIAL_EXPR(EXPR, 1)
diff --git a/src/SerializationFormat.cc b/src/SerializationFormat.cc
index 10dd4f29ea..271163d5db 100644
--- a/src/SerializationFormat.cc
+++ b/src/SerializationFormat.cc
@@ -107,6 +107,16 @@ bool BinarySerializationFormat::Read(int* v, const char* tag)
 	return true;
 	}
 
+bool BinarySerializationFormat::Read(uint8* v, const char* tag)
+	{
+	if ( ! ReadData(v, sizeof(*v)) )
+		return false;
+
+	*v = ntohs(*v);
+	DBG_LOG(DBG_SERIAL, "Read uint8 %hu [%s]", *v, tag);
+	return true;
+	}
+
 bool BinarySerializationFormat::Read(uint16* v, const char* tag)
 	{
 	if ( ! ReadData(v, sizeof(*v)) )
@@ -301,6 +311,13 @@ bool BinarySerializationFormat::Write(char v, const char* tag)
 	return WriteData(&v, 1);
 	}
 
+bool BinarySerializationFormat::Write(uint8 v, const char* tag)
+	{
+	DBG_LOG(DBG_SERIAL, "Write uint8 %hu [%s]", v, tag);
+	v = htons(v);
+	return WriteData(&v, sizeof(v));
+	}
+
 bool BinarySerializationFormat::Write(uint16 v, const char* tag)
 	{
 	DBG_LOG(DBG_SERIAL, "Write uint16 %hu [%s]", v, tag);
@@ -447,6 +464,12 @@ bool XMLSerializationFormat::Read(int* v, const char* tag)
 	return false;
 	}
 
+bool XMLSerializationFormat::Read(uint8* v, const char* tag)
+	{
+	reporter->InternalError("no reading of xml");
+	return false;
+	}
+
 bool XMLSerializationFormat::Read(uint16* v, const char* tag)
 	{
 	reporter->InternalError("no reading of xml");
@@ -530,6 +553,13 @@ bool XMLSerializationFormat::Write(char v, const char* tag)
 	return WriteElem(tag, "char", &v, 1);
 	}
 
+bool XMLSerializationFormat::Write(uint8 v, const char* tag)
+	{
+	const char* tmp = fmt("%" PRIu8, v);
+	return WriteElem(tag, "uint8", tmp, strlen(tmp));
+	}
+
+
 bool XMLSerializationFormat::Write(uint16 v, const char* tag)
 	{
 	const char* tmp = fmt("%" PRIu16, v);
diff --git a/src/SerializationFormat.h b/src/SerializationFormat.h
index f270b61bae..05cf56d961 100644
--- a/src/SerializationFormat.h
+++ b/src/SerializationFormat.h
@@ -23,6 +23,7 @@ public:
 	virtual void EndRead();
 
 	virtual bool Read(int* v, const char* tag) = 0;
+	virtual bool Read(uint8* v, const char* tag) = 0;
 	virtual bool Read(uint16* v, const char* tag) = 0;
 	virtual bool Read(uint32* v, const char* tag) = 0;
 	virtual bool Read(int64* v, const char* tag) = 0;
@@ -47,6 +48,7 @@ public:
 	virtual uint32 EndWrite(char** data);	// passes ownership
 
 	virtual bool Write(int v, const char* tag) = 0;
+	virtual bool Write(uint8 v, const char* tag) = 0;
 	virtual bool Write(uint16 v, const char* tag) = 0;
 	virtual bool Write(uint32 v, const char* tag) = 0;
 	virtual bool Write(int64 v, const char* tag) = 0;
@@ -92,6 +94,7 @@ public:
 	virtual ~BinarySerializationFormat();
 
 	virtual bool Read(int* v, const char* tag);
+	virtual bool Read(uint8* v, const char* tag);
 	virtual bool Read(uint16* v, const char* tag);
 	virtual bool Read(uint32* v, const char* tag);
 	virtual bool Read(int64* v, const char* tag);
@@ -106,6 +109,7 @@ public:
 	virtual bool Read(struct in_addr* addr, const char* tag);
 	virtual bool Read(struct in6_addr* addr, const char* tag);
 	virtual bool Write(int v, const char* tag);
+	virtual bool Write(uint8 v, const char* tag);
 	virtual bool Write(uint16 v, const char* tag);
 	virtual bool Write(uint32 v, const char* tag);
 	virtual bool Write(int64 v, const char* tag);
@@ -132,6 +136,7 @@ public:
 
 	// We don't write anything if tag is nil.
 	virtual bool Write(int v, const char* tag);
+	virtual bool Write(uint8 v, const char* tag);
 	virtual bool Write(uint16 v, const char* tag);
 	virtual bool Write(uint32 v, const char* tag);
 	virtual bool Write(int64 v, const char* tag);
@@ -152,6 +157,7 @@ public:
 
 	// Not implemented.
 	virtual bool Read(int* v, const char* tag);
+	virtual bool Read(uint8* v, const char* tag);
 	virtual bool Read(uint16* v, const char* tag);
 	virtual bool Read(uint32* v, const char* tag);
 	virtual bool Read(int64* v, const char* tag);
diff --git a/src/Serializer.h b/src/Serializer.h
index 72e0723880..719d4dc527 100644
--- a/src/Serializer.h
+++ b/src/Serializer.h
@@ -54,6 +54,7 @@ public:
 	DECLARE_WRITE(type)
 
 	DECLARE_IO(int)
+	DECLARE_IO(uint8)
 	DECLARE_IO(uint16)
 	DECLARE_IO(uint32)
 	DECLARE_IO(int64)