Within 40 s the Sperm Quality Analyzer (United Medical Systems, Santa Ana, CA, USA) provides a numerical value called the sperm motility index. This index reflects both the concentration of motile sperm cells and the intensity of their motility and cannot be determined by conventional semen analysis. To assess the diagnostic value and reliability of the sperm motility index, 155 ejaculates were investigated by the sperm quality analyzer and routine manual methods. The sperm motility index shows a good correlation with sperm density, motility, morphology, which are crucial parameters for male fertility.