Background: The present study aimed to determine the sexual risk profile of people using an automated, internet-based service that allows internet users to receive recommendations on sexually transmissible infection screening (‘Check your risk’ (CYR), http://www.checkyourrisk.org.au/), and to compare this with that of patients attending the Melbourne Sexual Health Centre (MSHC) for the first time over the same 6-month period: January–June 2006. Methods: The characteristics of those who used CYR and those who attended MSHC were compared using a χ²-test for categorical variables and the Mann–Whitney U-test for non-parametric data. Results: There were 2492 users who accessed CYR and 2735 who attended MSHC over the period. The age of CYR users was similar to that of MSHC patients when compared according to risk groups. The median number of recent sexual partners reported by CYR users was similar to and not significantly lower than that reported by MSHC patients. Of the 309 CYR users who provided a rating for the CYR site, 215 (70%) rated it as being ‘useful’ to ‘very useful’. Conclusions: Individuals who accessed an automated, internet-based sexual risk assessment service were at substantial risk for sexually transmitted infections, similar to those attending a sexual health service.