['To evaluate the association of FSH receptor polymorphism and ovarian response.', 'Retrospective study.', 'Academic research institute and private IVF clinic.', 'Fifty women were recruited in an assisted reproductive technology program (ART) and 100 proven fertile women of Indian origin.', 'Polymerase chain reaction, restriction fragment-length polymorphism for detecting polymorphisms at T(307)A and N(680)S.', 'FSH receptor polymorphisms, serum FSH, and estradiol levels, amount of FSH administered, occurrence of ovarian hyperstimulation syndrome (OHSS).', 'Prevalence of polymorphism at 307 position was 24%, 53%, and 23% in controls and 24%, 62%, and 14% in ART subjects for TT, TA, and AA, respectively, whereas at position 680, it was 31%, 56%, and 13% in controls and 42%, 46%, and 12% in ART subjects for NN, NS, and SS, respectively. The amount of FSH required for ovulation induction was low in AA compared with TT and TA subjects; the estradiol levels before and on the day of hCG administration were significantly higher. Eighty-five percent of the subjects with AA genotype developed OHSS.'] Is follicle-stimulating hormone receptor polymorphism ( Thr307Ala ) associated with variable ovarian response and ovarian hyperstimulation syndrome in Indian women?