<strong>Objectives: </strong>1. To investigate the incidence of antisperm antibodies (ASA) in a subfertile population in a Sri Lankan set up. 2. To determine the possible risk factors for the formation of ASA among them. <strong>Methods: </strong>A prospective descriptive study was carried out on subfertile couples treated at 'Prarthana', Centre for ART, during the period from 01.01.2006 to 01.01.2009. A total of 230 couples were included. Using an investigator administered questionnaire following information was obtained for each subject – demographic details, medical, surgical histories, genito-urinary infections, illnesses and medications, social habits etc. Presence of ASA was elicited using mixed antiglobulin reaction latex bead test (SpermMAR, Fertipro NV, Belgium) on spermatozoa, seminal plasma and serum of males and cervical mucus, serum and follicular fluid of females. <strong>Results: </strong>Out of 230 couples, 48 (20.86%) were positive for ASA. There were no significant associations observed between the presence of ASA and age, duration of marriage/subfertility, occupation, type of subfertility, associated autoimmune diseases, illnesses, and use of addictables in both males and females. Of the seven males who had undergone genital surgeries two were positive for ASA (Chisq= 4.407, P-value=0.036). A proportionately higher incidence of ASA was observed in females (11.7%) who had previous intra-uterine insemination (IUI) compared to females who did not have IUIs (5.88%). Markedly higher association of ASA was observed in females with pelvic inflammatory disease (PID) (20%) than PID free females (8%). <strong>Conclusion: </strong>Genital surgeries of men play a significant role in formation of ASA in males. Females who have undergone IUIs and who have had episodes of PID are at a greater risk in developing ASA. <strong>Key words: </strong>antisperm antibodies; incidence; risk factors. DOI: <a href="http://dx.doi.org/10.4038/sljog.v33i1.3998">http://dx.doi.org/10.4038/sljog.v33i1.3998</a> <em>SLJOG </em>2011; 33(1): 12-19<strong><em></em></strong>