Movement characteristics of human spermatozoa in fresh semen from 7 fertile men were studied using high-speed cinemicrography. Parameters that measured sperm swimming speed, flagellar beat frequency, flagellar beat shape, and the straightness of the swimming trajectory were obtained from frame-by-frame analysis of the cine films. In addition, each spermatozoon sampled for movement was also classified as being morphologically normal or abnormal, the latter being subdivided into the categories amorphous head, amorphous midpiece, elongated tapering head, piriform tapering head, megalocephalic and microcephalic. The morphological classification procedure involved direct reference of the sperm image on the screen of the cine film analysis console to metric morphological standards. Statistical analysis of the data investigated whether spermatozoa of different morphological types, as well as from different men, exhibited similar or dissimilar movement characteristics. It was found that morphologically normal spermatozoa swam faster and straighter, and exhibited higher beat frequencies than did morphologically abnormal sperm. These distinctions were most pronounced for spermatozoa with elongated or piriform tapering heads or amorphous midpieces.