Objectives: An integrated assessment of male infertility based on several parameters and the decision on ICSI application.Methods: Significant sperm parameters were selected and a male factor index(MFI) was devised in retrospective analyses of 271 IVF cycles (study I). The effectiveness of MFI was prospectively examined in 546 IVF cycles (study II). Finally, 54 cycles of ICSI were performed in patients with a 0 MFI (study III).Results: In study I, Significant correlations(R2 = 0.627) were demonstrated between the rate of fertilization by human IVF and five parameters (sperm concentration, motility, proportion of sperm with strictly normal morphology, hamster test, and the serum concentration of FSH). In study II, significant differences were observed among three groups of patients with 0, 1–2 and 3–5 MFI (20, 95 and 431 cycles, respectively) in the rates of fertilization (26.5, 51.3 and 65.2%, respectively), embryo transfer (30, 78 and 92.6%, respectively), and ongoing pregnancy (0, 18 and 28.3%, respectively). The rate of abortion was significantly higher in patients with a 0 MFI than in ones with an MFI of 1 to 5 (100 and 19%, respectively). In study III, ICSI significantly improved the rates of fertilization, embryo transfer, ongoing pregnancy and abortion (63.0, 98, 26 and 6.7%, respectively) in patients with a 0 MFI.Conclusion: MFI is useful in predicting IVF outcomes and patients with MFI 0 should be treated by ICSI.