Antenatal screening and treatment for sexually transmitted infections (STIs) has shown some benefits in countries where the practice is adopted. To date the prevalence of STIs in the Sudan is unknown. Our aims were to establish the prevalence of STIs among pregnant women in Khartoum (Sudan), to identify any risk factors and to suggest management. One hundred and fifty-one pregnant women were recruited for the study in an antenatal clinic in Khartoum in 1999. The prevalence of Chlamydia trachomatis, HIV, Trichomonas vaginalis, syphilis, Neisseria gonorrhoea and vulvo-vaginal candidiasis among the study population was established; 7.3% of patients suffered multiple infections. No risk factors for acquiring an STI were identified apart from genital ulcer disease. These findings suggest that a syndromic approach for treating STIs during pregnancy might not be possible. We conclude that STIs have a high prevalence among pregnant Sudanese women in Khartoum. The providers of health care in the Sudan need to revise their priority list.