An apparatus and method for processing a packet in a voice and data integration system are provided. The voice and data integration apparatus includes: a digital signal processor (DSP) for decoding a packet into PCM (pulse code modulation) data; and a host driver for receiving one or more packets from an Internet protocol (IP) network for a predetermined time, storing the received packets in storage regions in the order of sequence numbers, and transmitting the packets to the DSP in the order of the sequence numbers when the predetermined time has elapsed. Accordingly, a quality of voice in voice communication using the voice and data integration apparatus is guaranteed to a maximal extent.