We analyze the throughput of a combined hybrid-ARQ and link adaptive packet data transmission system. An analytical approach is used to develop a method for selecting transmit data rates that will maximize system throughput based on available channel state information and the maximum number of allowable transmissions. Performance of the system in the presence of channel estimation errors is also analyzed. Our results show that the availability of channel state information improves system performance significantly, especially under slowly fading channels or when the maximum number of transmissions allowed is small. We also show that, at low SNR, significant gain can be achieved by incorporating the knowledge of TV, the maximum allowable number of transmissions, into our data rate selection process. In addition, comparison to simulation results demonstrates that this approach can also be used to accurately evaluate performance of practical systems.