diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/std/MaxAggregateFunction.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/std/MaxAggregateFunction.java
index b21d5ad..df244e1 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/std/MaxAggregateFunction.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/std/MaxAggregateFunction.java
@@ -8,12 +8,14 @@
 import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AInt16SerializerDeserializer;
 import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AInt32SerializerDeserializer;
 import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AInt64SerializerDeserializer;
+import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AInt8SerializerDeserializer;
 import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
 import edu.uci.ics.asterix.om.base.AMutableDouble;
 import edu.uci.ics.asterix.om.base.AMutableFloat;
 import edu.uci.ics.asterix.om.base.AMutableInt16;
 import edu.uci.ics.asterix.om.base.AMutableInt32;
 import edu.uci.ics.asterix.om.base.AMutableInt64;
+import edu.uci.ics.asterix.om.base.AMutableInt8;
 import edu.uci.ics.asterix.om.base.ANull;
 import edu.uci.ics.asterix.om.types.ATypeTag;
 import edu.uci.ics.asterix.om.types.BuiltinType;
@@ -34,6 +36,7 @@
     private ICopyEvaluator eval;
     private boolean metInt8s, metInt16s, metInt32s, metInt64s, metFloats, metDoubles, metNull;
 
+    private byte byteVal = Byte.MIN_VALUE;
     private short shortVal = Short.MIN_VALUE;
     private int intVal = Integer.MIN_VALUE;
     private long longVal = Long.MIN_VALUE;
@@ -45,6 +48,7 @@
     private AMutableInt64 aInt64 = new AMutableInt64(0);
     private AMutableInt32 aInt32 = new AMutableInt32(0);
     private AMutableInt16 aInt16 = new AMutableInt16((short) 0);
+    private AMutableInt8 aInt8 = new AMutableInt8((byte) 0);
     @SuppressWarnings("rawtypes")
     private ISerializerDeserializer serde;
     private final boolean isLocalAgg;
@@ -58,6 +62,7 @@
     
     @Override
     public void init() {
+        byteVal = Byte.MIN_VALUE;
         shortVal = Short.MIN_VALUE;
         intVal = Integer.MIN_VALUE;
         longVal = Long.MIN_VALUE;
@@ -83,14 +88,17 @@
             switch (typeTag) {
                 case INT8: {
                     metInt8s = true;
-                    throw new NotImplementedException("no implementation for int8's comparator");
+                    byte val = AInt8SerializerDeserializer.getByte(inputVal.getByteArray(), 1);
+                    if (val > byteVal)
+                        byteVal = val;
+                    break;
                 }
                 case INT16: {
                     metInt16s = true;
                     short val = AInt16SerializerDeserializer.getShort(inputVal.getByteArray(), 1);
                     if (val > shortVal)
                         shortVal = val;
-                    throw new NotImplementedException("no implementation for int16's comparator");
+                    break;
                 }
                 case INT32: {
                     metInt32s = true;
@@ -175,7 +183,10 @@
                 aInt16.setValue(shortVal);
                 serde.serialize(aInt16, out);
             } else if (metInt8s) {
-                throw new NotImplementedException("no implementation for int8's comparator");
+                serde = AqlSerializerDeserializerProvider.INSTANCE
+                        .getSerializerDeserializer(BuiltinType.AINT8);
+                aInt8.setValue(byteVal);
+                serde.serialize(aInt8, out);
             } else {
                 // Empty stream. For local agg return system null. For global agg return null.
                 if (isLocalAgg) {