Packet-based and stream-based traffic will be widely accommodated in third generation mobile systems. In direct sequence code division multiple access (DS-CDMA) systems, the impact of packet-based traffic is different from stream-based traffic because of different power control schemes adopted in a multipath fading environment. In this paper, a closed-loop like power control scheme is considered for packet-based traffic on the reverse link. The concept of packet cost is introduced that represents how packet traffic consumes the link capacity of stream-based traffic. The effects of the response delay, the fading maximum Doppler frequency, and the number of resolvable paths on the packet cost for a single cell system are investigated by using Markov modeling for a multipath fading channel with a uniform power delay profile.