Regular condom use has been proven to remarkably reduce the transmission of sexually transmitted diseases (STDs) and its regular use for casual and commercial sex is important for the success of any STD/AIDS control programme. We studied the pattern of condom use among commercial sex workers in Ibadan, Nigeria in an attempt to identify the factors associated with it. Two hundred and ninety-five commercial sex workers in 21 brothels were randomly selected, using a multi-stage sampling technique, from a total of 31 identified in the 5 local government areas that make up Ibadan municipality. They were administered a pre-tested, semi-structured questionnaire by trained research assistants. Results showed that over half (53.2%) of the respondents were in the 20-29 year age group and most (71.5%) had been in the profession for less than a year. Sixty-five (22.0%) had no formal education, 29.8 % had some secondary education whilst 22.4 % had completed secondary school. Their overall knowledge of sexually transmitted diseases (STDs) was rated as poor (20.7%), moderate (64.1%) and good (15.2%). Their perceived risk of contracting HIV/AIDS was low (21.7%) although 87.8% regard it as a health problem in Nigeria. Eighty-three percent of the respondents always insisted that their clients used condoms, 13.2% did so frequently whilst 1.4% only occasionally. Of those who asked clients to use condoms, 69.5% of the women would refuse sex without condoms, 49 (16.6%) would do nothing and have sex without condoms, but 4.4% would charge extra money. No factor was found to have a significant association with the practice of asking clients to use condoms or of refusing sex without condoms. We concluded that consistent condom use was high among sex workers in brothels in Ibadan and was independent of the sex workers knowledge and perception of STDs.