We have developed a programming model that integrates concurrency with object-based programming. The model includes features for object definition and instantiation, and it supports concurrent executions of designated methods of the object instances. Yet, the model includes no specific communication or synchronization mechanism, except procedure call. The traditional schemes for communication, synchronization, interfaces among processes and accesses to shared memory can be encoded by objects in our model. Concurrency in the model is transparent to the programmer; the programmer believes that the program executes in a sequential manner whereas the implementation employs concurrent threads to gain efficiency.