Objectives: To estimate the extent of the homosexual and bisexual male population in inner Sydney and HIV prevalence within this population. Methods: Data from the 2000/2001 Sydney Gay Community Periodic Survey (SGCPS) and the Australian Study of Health and Relationships were used. Results: A re-analysis of responses from men in some inner east and inner west postcode areas of Sydney indicated that: the proportion of men who identified as homosexual or bisexual ranged from 4.4% to 48.1%; from 9.8% to 51.5% of men reported same-sex experiences during their lifetime; and 12.9% to 52.8% of men had ever experienced feelings of same-sex attraction. HIV prevalence among respondents to the SGCPS in these same areas varied from 9.1% to 21.3%. Conclusion: These findings indicate elevated proportions of men with same-sex identity, experience or attraction living in these inner Sydney locations compared with other geographic areas and illustrate how gay communities cluster.