Chlamydia trachomatis infection is a common sexually transmitted disease in Sweden, where counselling and partner notification are tools for prevention. Fifty infected patients (27 women, 23 men) were interviewed at an outpatient department. A majority of the patients felt that they were to blame for getting the disease and had the responsibility to inform partners. Women reacted more strongly against the disease and felt more negatively treated by the health care personnel. Chlamydia was considered a serious disease and 40% expressed fear for HIV/AIDS. Only eight per cent used condoms regularly. The concept 'causal contact' was very differently defined by the patients. Health personnel has to be more aware of the difficulties with ambiguous concepts and information need to be improved. More attention should be paid to women and their reactions.