Notifications of gonorrhoea in Victoria increased suddenly in the late 1990s, from an average of 375 cases per year from 1993 to 1997, to over 700 cases in 2000. This paper describes the susceptibility to ciprofloxacin of isolates of N. gonorrhoeae in Victoria from 1998 to 2001, and relates these to the reported epidemiologic characteristics of the cases. The proportion of all isolates of N. gonorrhoeae that was resistant to ciprofloxacin rose from 3 per cent in 1998 to 11 per cent in 2001. Among homosexual and bisexual men, resistant isolates remained rare (< 1 per cent). Among heterosexual men and women whose infection was acquired overseas, the proportion of resistant isolates increased from 14 per cent to 51 per cent. Among heterosexual men and women whose infection was acquired in Australia, the proportion of resistant isolates increased from 6 per cent to 14 per cent, and disproportionately involved persons born overseas. Patterns of antibiotic resistance are intimately linked to epidemiological characteristics of cases. Clinical treatment and public health and control strategies for resurgent sexually transmitted infections benefit from the insights of collaborative microbiological and epidemiological surveillance.