The aim of this study is to compare risk factors in new clients attending the walk-in triage-based day clinic (WITS) to those attending a telephone-triage appointment-based evening clinic of a sexual health service. The method involves an audit of computerized medical records of new clients attending between July 2002 and December 2007. There were 37,833 new clients of which 37,223 (98.4%) attended WITS and 610 (1.6%) attended the evening clinic. WITS clients were significantly older (31% vs. 30%, P < 0.041), more likely to be male (58% vs. 43%, P < 0.001), sex workers (6% vs. 3%, P < 0.001), not employed (34% vs. 10%, P < 0.001), diagnosed with gonorrhoea (1.7% vs. 0.7%, P < 0.041), herpes (4% vs. 2%, P < 0.000), non-specific urethritis (6% vs. 2%, P < 0.000) and less likely asymptomatic (35.1% vs. 53.4%, P < 0.001). Men attending WITS had significantly more female partners in the 12 months (3.9 vs. 3.0, P < 0.001), but other risks were similar in both clinics. A telephone-triage appointment-based evening clinic is important for asymptomatic high-risk individuals.