We have investigated the correlation of symptoms, signs and microscopy on the detection of Chlamydia trachomatis infection in men attending our clinic. One hundred and eleven men diagnosed with chlamydia over an 11-month period in our clinic were reviewed. Of these, 70 (63%) were symptomatic and 41 (37%) were asymptomatic. 84% (59/70) of symptomatic and 51% (21/41) of asymptomatic patients met the UK clinical criteria for diagnosis of non-gonococcal urethritis (NGU) and received treatment appropriate for chlamydia and NGU at their initial clinic visit. Our findings show that 19% (21/111) of men with Chlamydia trachomatis infection would leave the clinic untreated if a urethral smear preparation was not performed on those who were clinically asymptomatic at presentation. We feel that this is a sufficient argument to warrant continuing the current practice of testing asymptomatic men attending GUM clinics for NGU.