An apparatus and method for implementing picture-in-picture with frame rate conversion includes an input buffer unit, a data synchronizing unit, first through third memories, and a memory control unit. The input buffer unit buffers input data and outputs buffered data as first data and first data enabling signals. The data synchronizing unit synchronizes the first data output with an output clock signal and outputs synchronized data as second data and second data enabling signals. The first memory multiplexes the second data and outputs stored data in response to a first memory enabling signal. The second memory writes and reads data output from the first memory in response to a frame buffer control signal. The third memory outputs stored data as a display signal. The memory control unit controls data flow between the memories and frame rates of the input data.