The data from the B2 channel of the Stratospheric and Mesospheric Sounder (SAMS), flown on Nimbus 7, were intended to provide water vapor cross-sections ranging from 435¿S--65¿N in latitude and from 30--65 km in altitude. However, anomalous cross-sections obtained by Mutlow [1984> suggest that the in-flight transmittance behavior of the SAMS B2 channel was different from that expected. As a result a two-stage retrieval process has been developed to obtain both an improved estimate of the transmittance behavior of the channel, and the required water vapor cross-sections. The water vapor cross-sections obtained over the three-year period from January 1979--December 1981, clearly show the presence of a mid to high latitude summer maximum in water vapor at ~5--10 mb (~30--35 km), a poleward decrease in volume mixing ratios below ~10 mb (~30 km) in the winter hemisphere, a secondary maximum in the summer hemisphere at ~0.1 mb (~65 km) in the lower mesosphere, and a less distinct equatorial minimum at ~10 mb (~30 km). However, the latter has not been shown to be statistically significant in this analysis.