The objective was to examine how many young men who have sex with men (MSM) meet their first sexual partner through the Internet and whether this has increased over time. In 2003, 2505 MSM surveyed on UK Internet sites completed a self-administered questionnaire. Data were analysed for 810 MSM who were under 30 years old at the time of the survey and who first had sex with another man between 1993-2002. During this period there was a significant increase in the percentage of MSM who met their first male sexual partner through the Internet (2.6-61.0%). There was a corresponding decrease in the percentage who met their first sexual partner at a gay venue (34.2-16.9%), school (23.7-1.3%), a public sex environment, through small ads or telephone chatlines (10.5-1.3%). An increasing number of young MSM appear to meet their first sexual partner through the Internet. Online sexual health interventions should be developed targeting men early in their sexual careers.