Provided are an apparatus for receiving cable broadcasting programs and a multiplexer and a de-multiplexer thereof for reducing data amount processed in a Cable CARD and for correcting synchronization of descrambled data stream. The apparatus includes: a multiplexing unit for filtering a broadcasting stream to select only programs selected by a viewer and multiplexing the selected programs; a conditional-access processing unit for receiving the multiplexed streams and processing the multiplexed streams for conditional access (descrambling); and a de-multiplexing unit for de-multiplexing the multi stream from the conditional-access processing unit and correcting a program clock reference (PCR).