We aimed to describe and compare sexual links among people with gonorrhoea, by studying patients in 2 UK departments of genitourinary medicine. Interviews were completed for 510 and 235 cases in London and Sheffield respectively. There was a greater proportion of cases in men, homosexual men, non-white and non-British people and fewer female sex workers in London. Total networks of 1738 people in London and 570 people in Sheffield were described. Large linked heterosexual networks identified in Sheffield were associated with local contact, including men with higher numbers of sexual partners. Condom use for vaginal sex was reported for 11% of heterosexual partnerships in Sheffield, and 27% in London, with little difference between regular and casual partners. It was more difficult to define networks in London due to a high proportion of relatively anonymous contacts. These difficulties suggest that research and interventions may profitably focus upon venues for meeting partners as well as partner notification.