To compare the follicle diameter, the number of nature Follicle, quality of endometrium, quality of mucus cervix and a success rate of ovulation between clomiphene cirate (CC) and letrozole. Randomized controlled double blind trial was done parallel design non matching from Spetember 1st, 2007 until January 31st, 2008 in Dr, Kariadi General Hospital Semarang. Fourty infertile 31st, 2008 in Dr. …