Spermatozoa from healthy donors of proven fertility were analysed for percentage hyperactivation, mean curvilinear velocity (VCL), mean progressive velocity (VSL), amplitude of lateral head displacement (ALH) and percentage linearity (LIN) using two versions of the Hamilton-Thorn motility analyser (HTMA) running at different frame rates. The sort fraction criteria developed using a machine utilizing 30 Hz gave comparable figures for the percentage spermatozoa displaying motility patterns concomitant with hyperactivation when compared to that developed for a machine using a frame rate of 25 Hz. Statistically significant differences were observed when criteria developed using 30 Hz machines were transferred to those using 25 Hz. The frame rate dependency of VSL and VCL are thought to account for these differences; values for ALH and LIN were largely unaffected by frame rate. These results have implications for workers using the European version of the HTMA (at 25 Hz) with sort criteria, containing frame rate-dependent variables, which have been developed by American colleagues using the machines of a higher frame rate. More appropriate sort criteria for workers using European (25 Hz) machines are suggested.