OBJECTIVE: To evaluate predictor of IVF outcomes following single embryo transfer in patients with decreased ovarian reserve. METHODS: A retrospective review was performed in 919 IVF cycles with elevated basal serum FSH ( > or = 12 mIU/mL), the number of retrieved oocytes < or =4 and serum E2 concentration on hCG day <500 pg/ml between Jan. 1996 and Dec. 2006. Two hundred thirty five IVF cycles following single embryo transfer were included. Pregnancy rates and live birth rates was evaluated according to maternal age, serum E2 on hCG day, basal FSH level, the number of blastomere on day 3 ET, stimulation protocol, the number of cycles of ET. Statistical analysis was used SPSS 12.0 program. RESULTS: OPU cancellation rates were 25.6% (235 cycles), OPU failure rates were 18.5% (170 cycles), embryo transfer cancellation rates were 14.0% (129 cycles). Pregnancy rates following single embryo transfer was 8.1% (19 cycles) and live birth rates was 4.7% (11 cycles). Pregnancy rates and live birth rates of women under 35 years old was statistically higher than those of women above 35 years old (20% vs. 3.5% (p<0.0001), 12.3% vs. 1.8%, (p=0.002)). There was no difference in basal FSH, serum E2 on hCG day, and the number of blastomere on ET, and stimulation protocol. Cumulative pregnancy rates according to the number of cycles of ET were 1st 8.1%, 2nd 9.2%, 3rd 9.7%, 4th 9.0%, and 5th 9.5%. CONCLUSION: Pregnancy rates and live birth rates of IVF-ET cycles following single embryo transfer in patients with decreased ovarian reserve are statistically increased in women under 35 yrs old. There is no difference in cumulative pregnancy rates. These data may be helpful for counseling women with decreased ovarian reserve in attempting IVF with their own eggs or when choosing donor oocytes.