From the second half of 20th century, methods of ovulation induction progressed markedly, the most commonly used drug is clomiphene citrate with triggering of ovulation by hCG. Tamoxifen and Cyclofenil are similar drugs to clomiphene. Aromatase inhibitors are recently introduced with promising effects. Cases that fail to respond to clomiphene are candidates for gonadotropin treatment either human menopausal gonadotropins, urinary follicle stimulating hormone or recombinant human follicle stimulating hormone. Also, GnRH, its agonists and antagonists are widely used nowadays in ART protocols. Ovarian surgical procedures, as ovarian drilling, are also tried. Ovulation induction is not free of complications, the most serious of which is ovarian hyperstimulation syndrome and possibly cancer. The most important step in the management of OHSS is its prevention by recognizing its high-risk profile.