This study describes the attitudes to risk behaviour among patients diagnosed with a chlamydia infection at a sexually transmitted infection (STI) clinic. Qualitative interviews were conducted face to face with 18 participants, aged 18–30 years, with a confirmed diagnosis of chlamydia infection. An interview guide was used and participants described the behaviour that had led to their infection. Qualitative content analysis was performed on the theme of risk. A common denominator among participants was risky behaviour in sexual relations when using alcohol, while very few participants took unnecessary risks in life in general. Of the 18 participants, 16 had been tested for STIs previously, and 10 had previously had an STI.