This study aimed to study the effects of age and body mass index on infertility, preovulatory endometrial thickness, and pregnancy outcome after ovulation induction/intrauterine insemination. Twenty unexplained infertility women and thirty polycystic ovary syndrome women subjected to ovulation induction/intrauterine insemination were enrolled in this study. Only two polycystic ovarian syndrome women (4%) became pregnant. There was significant effect of age on endometrial thickness for unexplained infertility and polycystic ovarian syndrome women (P=0.02, P=0.05, respectively). Body mass index and endometrial thickness were independent factors for unexplained infertility and polycystic ovarian syndrome women (P=0.26, P=0.4, respectively). Age adversely affected endometrial thickness while body mass index was not correlated with endometrial thickness