OBJECTIVE: To prove that several days of low-dose hCG alone can be used to stimulate folliculogenesis, complete FSH-initiated follicle/oocyte maturation, and achieve pregnancy in assisted reproduction technology. DESIGN: Case report. SETTING: Reproductive endocrinology center at an academic institution. PATIENT(S): A 35-year-old female patient and her partner with male-related infertility. INTERVENTION(S): After an 8-day priming with hMG (225 IU/d), we administered low-dose hCG (200 IU/d) alone for 5 days in one GnRH-agonist suppressed patient until proper follicle development was obtained and intracytoplasmic sperm injection was performed. MAIN OUTCOME MEASURE(S): Daily serum levels of LH, FSH, hCG, E(2), P, and T; measurements of follicle number and size; oocytes retrieved and fertilized; pregnancy. RESULT(S): Although FSH levels rapidly declined after hMG discontinuation, E(2) and large follicles increased during hCG-only administration. Several good quality oocytes were retrieved and fertilized by intracytoplasmic sperm injection; three embryos were transferred and a twin pregnancy ensued. CONCLUSION(S): Replacement of FSH with low-dose hCG for several days in the late ovulation induction stages of assisted reproduction technology resulted in: [1] continued growth of large ovarian follicles and E(2); [2] an optimal preovulatory follicle pattern consisting of many large and few medium and small follicles; and [3] reproductively competent oocytes and pregnancy.