The objective of this study was to evaluate trends in the availability of socially marketed condoms in urban Tanzania, and to assess the effect of changes in the social marketing programme's strategy for distributing condoms to retail outlets. Three retail outlet surveys conducted in urban Tanzania in 1996/97, 1998 and 1999 were analysed. Multiple Classification Analysis (MCA) was used to determine changes in availability of condoms, after adjusting for differences in the composition of the samples. Consistent with the changes in the condom social marketing distribution system, the proportion of condom outlets that were supplied by wholesalers increased from 42% in 1997 to 60% in 1999. The increasing use of wholesalers allowed sales agents to devote more time to opening new outlets. Hence, the percentage of outlets that had been solicited to sell condoms by social marketing condom sales persons increased from 14% in 1997 to 25% in 1999. Following these changes in the distribution system, the percentage of outlets selling socially marketed condoms increased from 25% to 32% between 1997 and 1998, and stabilized at that level. More detailed examination showed that availability of socially marketed condoms increased significantly in most non-traditional outlets, and in all regions of the country. In conclusion, distribution survey data indicate that changes in the distribution system increased the role of wholesalers, and enabled sales teams to allocate more time to soliciting new condom outlets. Concurrent with these changes, the availability of socially marketed condoms in non-traditional retail outlets increased significantly. Regular monitoring of condom availability can ensure that any emerging supply problems are identified and remedied quickly.