The rationale behind intrauterine insemination (IUI) with partner sperm is bypassing the cervical-mucus barrier and increasing the number of motile spermatozoa with a high proportion of normal forms at the site of fertilization. This chapter examines the value and position of homologous intrauterine insemination in an assisted reproductive technology (ART) program. Some of the factors influencing IUI success include site of insemination, number of inseminations, exact timing of IUI, sperm preparation methods and fallopian tube sperm perfusion. Artificial inseminations can be done intravaginally, intracervically (ICI), pericervically using a cap, intrauterine (IUI), transcervical intrafallopian (IFI) or directly intraperitoneal (IPI). Most studies refer to IUI, which seems to be an easy and better way of treatment. IUI should be promoted as the best first-line treatment in most cases of subfertility provided at least one tube is patent and an IMC after sperm preparation of more than 1 million can be obtained.