IUI involves obtaining a semen sample from the male partner at the time of ovulation, preparing it in the laboratory and then placing it in the woman's uterus. During sperm preparation, dead and poor quality sperm are removed leaving a small, highly purified sample of healthy sperm, at the correct concentration for fertilization. This is then placed into the uterine cavity using a very soft, thin catheter (a procedure quite similar to having a smear test).

Intra-uterine insemination must be performed at the time of ovulation and so requires accurate timing. As described above, the woman's cycle is monitored via vaginal ultrasound scanning. IUI may be performed during a 'natural' cycle or in combination with fertility drugs such as Clomid or FSH/LH injections.

IUI is recommended for certain problems such as mild sperm abnormalities, cervical problems or psycho-sexual problems. It may also be used for unexplained infertility. It is not suitable if there is significant endometriosis (grades III – IV), tubal disease (eg following tubal infection) or significant sperm abnormalities.