To assess the knowledge of mothers of under-five children brought to immunisation centres of contraceptive methods applicable by males and their perceptions of the roles of males in family planning.This cross-sectional descriptive study involved a questionnaire interview of mothers who came to immunise their children at five public immunisation centres in Port Harcourt. Data entry and analysis employed EPI-Info version 6.Amongst the 558 mothers interviewed, the contraceptive prevalence rate was 5.6% and 85.6% of them knew at least a family planning method for males. About 15.8% would depend on their spouses for choice of contraceptive methods and 52.7% would discontinue family planning if their spouses objected. About 33.5% of the spouses had used some form of contraception while only 22.1% of the females recognised that male involvement could impact on the acceptance rate of family planning services. Despite their knowledge of safe child spacing, about 53% of the respondents delivered within shorter intervals and had significantly more pregnancies/children that they would have had if they were in 'control' of their reproductive health decisions. The spouses, despite being significantly older, more educated, with higher level jobs, and in-charge of the reproductive health decision in the home, did not contribute to the knowledge of the women and their practices of family planning.Despite the advantaged position of males in family matters, their roles in family planning remains largely unutilised. If the acceptance of family planning must improve, males should also be targeted by family planning programmes.