Objective: To describe the first birth achieved after intracytoplasmic sperm injection (ICSI) of cryopreserved human oocytes. Design: Case report. Setting: University of Bologna Hospital, Department of Obstetrics and Gynecology, Reproductive Endocrinology Unit, IVF and Infertility Center. Patient(s): One patient undergoing IVF. Intervention(s): Transvaginal ultrasound-guided oocyte retrieval followed by oocyte freezing. Artificial preparation of the endometrium with E-2 and P, oocyte thawing, and ICSI. Result(s): Four of 12 cryopreserved oocytes survived; using ICSI, 2 underwent normal fertilization but only 1 cleaved. One good-quality 4-cell embryo was transferred. A single gestation was confirmed by ultrasound at the 7th week. Amniocentesis was performed at the 16th week and demonstrated a normal female karyotype of 46,XX. After a normal pregnancy, a healthy female infant was born at the 38th week of gestation. Conclusion(s): The combination of ICSI and oocyte cryopreservation is a new tool in assisted reproductive technology. (C) 1997 by American Society for Reproductive Medicine.