OBJECTIVE: PGD results significantly decrease the number of embryos available for transfer by 30-70%. Thus, optimizing ovarian stimulation for IVF with PGD may improve outcome. We investigated if the ovarian stimulation protocol used for IVF and the number of oocytes retrieved affect embryos' aneuploidy rate. DESIGN: Retrospective study. MATERIALS AND METHODS: 251 consecutive cycles of women age 22–47 years who underwent IVF/ICSI with PGD for aneuploidy were reviewed. Before treatment, patients' ovarian reserve were estimated based on age, antral follicle count and day-3 FSH level, and, accordingly, changes were implemented in the stimulation protocol or in medication dosage to try to safely improve oocyte yield (to 10-15 oocytes). The data was analyzed by age, number of oocytes retrieved, and type of ovarian stimulation protocol used: long mid-luteal Lupron, antagonist, or Micro-dose Lupron. The primary endpoints were embryos' aneuploidy rate and clinical pregnancy rate (+FHT). RESULTS: 1905 oocytes/embryos of women age < 43 years old were tested. Within the age groups of < 35 and 35-42 years old, the aneuploidy rates were similar and independent of the number of oocytes retrieved, ≤ 7, 8-15, 16-20, or ≥ 21 oocytes: 53%, 56%, 54%, 56% and 69%, 69%, 72%, 68%, respectively. The percent of cycles with ET increased with the increase number of oocytes retrieved. Within these age groups, comparable aneuploidy rates were obtained with the different stimulation protocols: 58%, 52%, 52% and 68%, 73%, 71% for the Lupron, antagonist, and Micro-dose protocols, respectively. The clinical pregnancy rates at age < 35 were 41%, 37%, 44% and at 35-42 years 26%, 33%, 35% for the patients with Lupron, antagonist, Micro-dose protocols, respectively. CONCLUSIONS: The ovarian stimulation protocol used for IVF and the number of oocytes retrieved had no effect on oocytes/embryos' aneuploidy rate. Individually adjusted ovarian stimulation based on estimated ovarian reserve for patients undergoing IVF-PGD may improve outcome. Prospective, randomized trials are needed. Maximizing oocyte yield seems to increase the chance to generate a sufficient number of chromosomally normal embryos for transfer.