Media for sperm capacitation and in-vitro fertilization (IVF) are supplemented by proteins (albumin, globulins) extracted from human or animal sera, which raises the problem of potential contamination by pathogens. The present study aimed to evaluate the efficiency of a protein-free medium (SMART1, Bio-Media, Boussens, France) and to compare it with a human serum albumin (HSA) containing medium (FertiCult, FertiPro NV, Aalter, Belgium). In the first part of the study, media were compared for their ability to support human sperm functions. Total motility, progressive motility and rapid motility were no different between media after a 30 min and a 4 h incubation, but were significantly reduced using SMART1 after a 24 h incubation. However, the kinematic parameters (straight line velocity, mean path velocity, curvilinear velocity and mean amplitude of lateral head displacement) were significantly lower using SMART1, whatever the incubation time. The spontaneous acrosome reaction and the acrosome response to A23187 ionophore were similar in both media. In the second part of the study, media were compared in a randomized trial in 93 IVF attempts. No significant difference was found in the transfer per attempt rate (92 versus 87% respectively for SMART1 and FertiCult, NS) but the percentage of fertilized oocytes was significantly higher using SMART1 (65 versus 55% respectively for SMART1 and FertiCult, P < 0.01). The percentage of embryos with a fair morphology was identical in both media (30 versus 30% respectively for SMART1 and FertiCult, NS). In conclusion, despite a decrease in sperm kinematics, SMART1 medium allows an increase in fertilization rate and, since it is devoid of any human or animal compound, may be preferable for human use.