Our objective was to evaluate the results of in vitro fertilization (IVF) cycles in the elderly (43-45 years old) female population. All consecutive women aged 43-45 years admitted to our IVF unit from January 1996 to December 2001 were enrolled in the study. Ovarian stimulation characteristics, number of oocytes retrieved, number of embryos transferred and pregnancy rate were assessed. Seven hundred and eight consecutive IVF cycles in 276 patients were evaluated. Two hundred and seven cycles were cancelled (cancellation rate 29.2%). Forty-seven patients achieved a clinical pregnancy (pregnancy rate 6.6% per cycle and 9.4% embryo transfer) with a 30% live birth rate. In patients who underwent embryo transfer, there were no differences between conception and non-conception cycles in patient's age, number of gonadotropin ampules used, length of ovarian stimulation, number of oocytes retrieved, fertilization rate or cleavage rate. However, the conception cycles were associated with a significantly lower peak estradiol level (p < 0.04) and higher number of total (p < 0.03) and good-quality (p < 0.005) embryos transferred, in addition to a lower ratio of estradiol level/number of follicles > 14 mm on day of human chorionic gonadotropin administration and of estradiol level/number of oocytes retrieved. We conclude that, although older female age is a major contributor to IVF failure, successful IVF cycles can be expected in patients aged 43-45 years in the presence of low ratios of peak estradiol to either number of follicles > 14 mm on day of human chorionic gonadotropin administration or number of oocytes retrieved that reach the stage of embryo transfer with at least two good-quality embryos.