AbstractThe effect of increasing concentrations of amylase on the percentage of active spermatozoa, the quality of their motility and the percentage of viable cells was studied in semen samples in vitro. The amount of amylase needed to liquefy viscous semen samples in vitro also was determined.The percentage of active spermatozoa and viable cells, and the quality of sperm motility were altered in relationship to the amylase levels. Significant decreases in these parameters compared to control values were seen at the higher concentrations of amylase. The lowest level of amylase did not alter these parameters significantly and was sufficient to liquefy 80 per cent of the viscous semen samples. Amylase appears to be effective at low concentrations for use in liquefying viscous semen samples, thus making them easier to analyze during routine semen examination. The level of amylase used and the interval between addition and analysis must be controlled carefully.