What is unexplained infertility. This is a diagnosis of exclusion. Here all the basic tests like documentation of ovulation by USG, confirming tubal patency by hysterosalpingography , postcoital test for assessment of cervical factor, ruling out endometriosis and assessment of male factor by semen examination has been done and found to be normal. Intrauterine insemination is one of the modes of treatment in unexplained infertility.