The proportion of homosexually acquired cases of primary and secondary syphilis in patients attending venereal disease clinics in the United Kingdom has risen from 42.4% to 54% over a six-year period. Similarly, over the same period, the proportion of homosexually acquired cases of gonorrhoea has risen from 9.8% to 10.9%. The increase in incidence of homosexually acquired infections in both diseases occurred in all areas but particularly in London. Thus the very considerable epidemiological importance of male homosexuals as a high-risk group should receive more, not less, emphasis.