Intrauterine insemination (IUI) is a widely used fertility treatment for couples with male and/or non-male factor infertility and is a relatively simple and inexpensive procedure. When used for unexplained infertility, IUI combined with ovarian stimulation increases the pregnancy rates, but evidence does not support this to be true when applied for male factor infertility. Recently, the revised World Health Organization laboratory manual for semen criteria provided a new insight for practical guidelines. Further randomized, controlled studies are necessary to develop standardized IUI strategies. The authors reviewed, via literature search, on the indications, prognostic factors, ovarian stimulation protocols, and methods that have been employed for IUI treatment.