Data on sexual practices in the past two months were obtained from 176 Australian and 159 New Zealand homosexually active men. Factor analysis yielded three major underlying dimensions of homosexual behaviour in each sample, accounting for 53.4 and 54.0% of total variance at baseline and 55.1 and 62.1% at follow-up, respectively. These three dimensions represented unsafe sex involving predominantly anal activity, safe (oral and mutual masturbatory) sex without condoms, and safe anal sex with condoms and withdrawal. Comparison of the four matrices (two countries by two times), using Cattell's S index, indicated high stability of the factor structure across countries and times. These three dimensions of homosexual behaviour appear to represent consistent behavioural clusters across samples and times. They suggest that use of these dimensions in further research on homosexually active men is warranted and that homosexual activities cluster into a number of limited dimensions on which sexual behaviours are interrelated.