Ovulation induction is the stimulation of the ovaries to grow one or more eggs with the use of medications, either oral or injectable which increase the chances of conception. Ovulation induction is needed for those patients who do not ovulate on their own either because of PCOD, stress or weight fluctuations. It is also needed for those with unexplained infertility and for IUI to increase the number of eggs released in a cycle which again increases the chances of pregnancy. The commonly used oral drugs are Clomiphene citrate, Letrozole, Tamoxifen and Anastrozole. They are usually started from 3rd day of periods and are given for 5 days. The injectable drugs are the hormones FSH/HMG. Ovulation induction also requires monitoring of the growth of the eggs with serial follicular scans and triggering the ovulation with HCG injection once the eggs grow to an appropriate size. The common side effect is the occurrence of multiple pregnancy and rarely OHSS (ovarian hyperstimulation syndrome).