IUI has been associated with a pregnancy rate of 10–20% per patient, with wide variation, especially in patients undergoing super ovulation for unexplained infertility, female age and amount of motile sperm while receiving adequate luteal phase support. The current study was planned as an epidemiological survey to determine the success rate of IUI when supported with oral natural or synthetic progesterone. Consecutive sixty IUI cycles in women with unexplained infertility were evaluated for serum progesterone levels while assessing the pregnancy rates following the insemination procedure. Patients received either oral natural micronized progesterone sustained release or synthetic progestin (Dydrogesterone) formulation once or twice a day respectively for two to four weeks till the next menses. Pregnancy was confirmed by urinary & biochemical investigation. Three (5%) cases had pregnancy at the first IUI cycle. Sr. Progesterone levels were maintained at ≥14 ng/ml for 56 (93.3%) patients during the mid-luteal phase. There were no side effects reported during the luteal phase administration of oral progesterone. The pregnancy rates could be related to strategy for monofollicular development, first cycle assessment and trend for a lower motile fraction noted in the current study.