In order to determine the sources through which patients learned about vasectomy, the men who had a vasectomy at the Manchester Family Planning Association between January 1973 and September 1974 were surveyed. The sources of information through which the patients heard about vasectomy are as follows: publicity was the source in 35.5% of the cases; the family doctor was the source in 21.7% of the cases; a friend or a clinic patient was the source in 19.3% of the cases; transfer from family planning clinic was the source in 12.3% of the cases; the local authority clinic was the source in 7.8% of the cases; and "other" was the source in 3.5% of the cases. Although "publicity" was the most common source of information for both manual and non-manual workers, there was a significant difference between the sources of referral of these 2 groups, being the proportion of non-manual workers (42.2%) whose source was publicity, compared with the manual workers (31.0%). Although there was no longer an overall significant difference when all sources of information were analyzed by social class, clearly there is a relationship between social class and the likelihood of publicity being the motivating influence.