Ovarian stimulation aims to develop one or more ovarian follicles to reach maturity stage thus enabling release of one or more oocytes ready for fertilisation. It has been used in anovulatory cycles, IUI and ART. The pharmacological agents include oral agents and injectables. The dosage varies according to the planned cycle. Currently the individualised controlled ovarian stimulation in IVF remains the most suitable option. The basics of ovarian stimulation, protocols, advantages and drawbacks will be further discussed.