diff --git a/pvDataApp/Makefile b/pvDataApp/Makefile
index 5d06118..e9b07ff 100644
--- a/pvDataApp/Makefile
+++ b/pvDataApp/Makefile
@@ -25,6 +25,8 @@ INC += timer.h
 INC += queueVoid.h
 INC += queue.h
 INC += messageQueue.h
+INC += destroyable.h
+INC += status.h
 
 LIBSRCS += byteBuffer.cpp
 LIBSRCS += bitSet.cpp
@@ -106,6 +108,10 @@ SRC_DIRS += $(PVDATA)/pvMisc
 INC += bitSetUtil.h
 LIBSRCS += bitSetUtil.cpp 
 
+SRC_DIRS += $(PVDATA)/monitor
+INC += monitor.h
+
+
 LIBRARY=pvData
 
 pvData_LIBS += Com
diff --git a/pvDataApp/misc/destroyable.h b/pvDataApp/misc/destroyable.h
new file mode 100644
index 0000000..e2a63a3
--- /dev/null
+++ b/pvDataApp/misc/destroyable.h
@@ -0,0 +1,25 @@
+/* destroyable.h */
+/**
+ * Copyright - See the COPYRIGHT that is included with this distribution.
+ * EPICS pvDataCPP is distributed subject to a Software License Agreement found
+ * in file LICENSE that is included with this distribution.
+ */
+#ifndef DESTROYABLE_H
+#define DESTROYABLE_H
+namespace epics { namespace pvData { 
+
+
+        /**
+         * Instance declaring destroy method.
+         * @author mse
+         */
+        class Destroyable  {
+            public:
+            /**
+             * Destroy this instance.
+             */
+            virtual void destroy() = 0;
+        };
+
+}}
+#endif  /* DESTROYABLE_H */
diff --git a/pvDataApp/misc/status.h b/pvDataApp/misc/status.h
new file mode 100644
index 0000000..6d2ca45
--- /dev/null
+++ b/pvDataApp/misc/status.h
@@ -0,0 +1,70 @@
+/* status.h */
+/**
+ * Copyright - See the COPYRIGHT that is included with this distribution.
+ * EPICS pvDataCPP is distributed subject to a Software License Agreement found
+ * in file LICENSE that is included with this distribution.
+ */
+#ifndef STATUS_H
+#define STATUS_H
+
+#include "serialize.h"
+
+namespace epics { namespace pvData { 
+
+    	/**
+    	 * Status type enum.
+    	 */
+    	enum StatusType { 
+                /** Operation completed successfully. */
+                OK,
+                /** Operation completed successfully, but there is a warning message. */
+                WARNING,
+                /** Operation failed due to an error. */
+                ERROR,
+                /** Operation failed due to an unexpected error. */
+                FATAL
+    	};
+
+        /**
+         * Status interface.
+         * @author mse
+         */
+        class Status : public epics::pvData::Serializable {
+            public:
+
+            /**
+             * Get status type.
+             * @return status type, non-<code>null</code>.
+             */
+            virtual StatusType getType() = 0;
+
+            /**
+             * Get error message describing an error. Required if error status.
+             * @return error message.
+             */
+            virtual epics::pvData::String getMessage() = 0;
+
+            /**
+             * Get stack dump where error (exception) happened. Optional.
+             * @return stack dump.
+             */
+            virtual epics::pvData::String getStackDump() = 0;
+
+            /**
+             * Convenient OK test. Same as <code>(getType() == StatusType.OK)</code>.
+             * NOTE: this will return <code>false</code> on WARNING message although operation succeeded.
+             * To check if operation succeeded, use <code>isSuccess</code>.
+             * @return OK status.
+             * @see #isSuccess()
+             */
+            virtual bool isOK() = 0;
+
+            /**
+             * Check if operation succeeded.
+             * @return operation success status.
+             */
+            virtual bool isSuccess() = 0;
+        };
+
+}}
+#endif  /* STATUS_H */
diff --git a/pvDataApp/monitor/monitor.h b/pvDataApp/monitor/monitor.h
new file mode 100644
index 0000000..d2fc0f6
--- /dev/null
+++ b/pvDataApp/monitor/monitor.h
@@ -0,0 +1,94 @@
+/* monitor.h */
+/**
+ * Copyright - See the COPYRIGHT that is included with this distribution.
+ * EPICS pvDataCPP is distributed subject to a Software License Agreement found
+ * in file LICENSE that is included with this distribution.
+ */
+#ifndef MONITOR_H
+#define MONITOR_H
+
+#include <status.h>
+#include <destroyable.h>
+
+namespace epics { namespace pvData { 
+
+    /**
+     * Class instance representing monitor element.
+     * @author mrk
+     */
+    class MonitorElement {
+        public:
+        /**
+         * Get the PVStructure.
+         * @return The PVStructure.
+         */
+        virtual PVStructure* getPVStructure() = 0;
+        /**
+         * Get the bitSet showing which fields have changed.
+         * @return The bitSet.
+         */
+        virtual BitSet* getChangedBitSet() = 0;
+        /**
+         * Get the bitSet showing which fields have been changed more than once.
+         * @return The bitSet.
+         */
+        virtual BitSet* getOverrunBitSet() = 0;
+    };
+    
+    
+    /**
+     * Interface for Monitor.
+     * @author mrk
+     */
+    class Monitor : public Destroyable, private NoDefaultMethods {
+        public:
+        /**
+         * Start monitoring.
+         * @return completion status.
+         */
+        virtual Status* start() = 0;
+        /**
+         * Stop Monitoring.
+         * @return completion status.
+         */
+        virtual Status* stop() = 0;
+        /**
+         * If monitor has occurred return data.
+         * @return monitorElement for modified data on null if no monitors have occurred.
+         */
+        virtual MonitorElement* poll() = 0;
+        /**
+         * Release a MonitorElement that was returned by poll.
+         * @param monitorElement
+         */
+        virtual void release(MonitorElement* monitorElement) = 0;
+    };
+    
+    
+    /**
+     * Requester for ChannelMonitor.
+     * @author mrk
+     */
+    class MonitorRequester : public Requester {
+        public:
+        /**
+         * The client and server have both completed the createMonitor request.
+         * @param status Completion status.
+         * @param monitor The monitor
+         * @param structure The structure defining the data.
+         */
+        virtual void monitorConnect(Status* status, Monitor* monitor, Structure* structure) = 0;
+        /**
+         * A monitor event has occurred. The requester must call Monitor.poll to get data.
+         * @param monitor The monitor.
+         */
+        virtual void monitorEvent(Monitor* monitor) = 0;
+        /**
+         * The data source is no longer available.
+         * @param monitor The monitor.
+         */
+        virtual void unlisten(Monitor* monitor) = 0;
+    };
+
+}}
+#endif  /* MONITOR_H */