Innovative and non-stigmatizing interventions are required to reduce ethnic inequalities in rates of sexually transmitted infections among young people. We therefore designed an intervention, 'You can't tell by looking,' which combined health promotion with testing for gonorrhoea and chlamydia using nucleic acid amplification technology and treatment and partner notification delivered in the non-clinical settings. One hundred and eighty-one participants were seen in 13 sessions in local further education colleges. Forty-three percent of participants were from Black Caribbean or Black Other ethnic groups and 39% were Black African: 125 of 181 participants were sexually active and 109 of these (87%) provided a urine specimen. 10/109 (9.2%, 95% confidence interval 4.5-16.2%) samples were confirmed positive for Chlamydia trachomatis and two were also positive for Neisseria gonorrhoeae. Only 7% of those tested found it embarrassing. The intervention was both feasible and acceptable to young people. It could be tested in a wider variety of non-clinical settings and evaluated in a cluster randomized trial.