The Doppler coefficient of reactivity is a crucial parameter in the evaluation of several transients in light water reactors (LWRs). It is relatively small in magnitude and cannot be measured directly in operating reactors. Doppler coefficients are presented for slightly idealized pressurized water reactor pin cells. These coefficients were calculated with the MCNP-3A continuous-energy Monte Carlo code using data taken directly from the ENDF/B-V nuclear data library. This combination represents the most rigorous analytical tool and the best nuclear data available. Consequently, these results comprise a set of numerical benchmarks that may be used to evaluate the accuracy of LWR lattice physics codes in predicting Doppler behavior at operating conditions. An example of one such evaluation, using the CELL-2 code, is included.