This chapter focuses on in vitro fertilisation (IVF), the most common assisted reproductive technology (ART) procedure. The use of IVF has radically transformed the way in which we approach the management of infertility, irrespective of the diagnosis, and it is integral to the infrastructure of a modern fertility service. Monitoring of treatment includes follicle tracking with ultrasound and ovarian steroid measurement. In the early days of IVF, oocyte collection procedures were done under laparoscopic guidance. After oocyte retrieval, freshly ejaculated seminal fluid is prepared to concentrate motile spermatozoa in a fraction that is free of seminal plasma and debris. Embryologists then have to decide whether they are going to perform conventional IVF or need to inject sperm directly into the oocyte (intracytoplasmic sperm injection (ICSI)). Two major complications of ART to consider are multiple pregnancy and ovarian hyperstimulation syndrome (OHSS).