OBJECTIVES: The purpose of this study is to investigate the clinical significance of age and basal serum FSH in predicting the outcomes of in vitro fertilization (IVF) in patients with poor-ovarian response. METHODS: From January 2000 to December 2004, 85 second IVF cycles of 85 poor-ovarian response patients under the age of 42 with a back-ground of the first IVF cycles at our infertility center and 5 or less oocytes were retrieved and their basal serum FSH levels of 15~25 mIU/ml were enrolled in this study. Exclusion criteria were patients with a male factor for the etiology of infertility and undergoing genetic diagnosis of embryo such as PGD. Flare-up protocol was used for ovarian stimulation in all cases. RESULTS: When we stratified the study groups by patient's age, the younger age group (age < 35, n=35) showed significantly higher implantation rate (19.0% versus 4.0%, p<0.05) and higher ongoing pregnancy rate (100% versus 14.3%, p<0.05) than the older age group (age > or = 35, n=50). And then, when we stratified the study populations by basal serum FSH level, the lower FSH group (basal serum FSH < 20 mIU/ml, n=58) showed significantly higher number of retrieved oocytes (4.6+/-0.7 versus 2.2+/-0.5, p<0.05) and lower cancellation rate (19.0% versus 55.6%, p<0.05) than higher FSH group (basal serum FSH > or = 20 mIU/ml, n=27). CONCLUSIONS: In conclusion, it was suggested that the patient's age could predict the IVF outcomes in respect to its potency of pregnancy and ongoing pregnancy. Serum basal FSH levels could predict more accurately the ovarian response of cycle, but not clinical outcomes.