The objective of this study was to determine the effect of herd, breed, the age of rams, their semen density, and the type of diluter used on sperm motility during a survival test. The total level of sperm ac­ti­vi­ty of 49 rams was evaluated. A statistically significant effect of the herd, breed, the age of the rams, and the density of their semen on sperm motility after 30, 60, and 90 minutes was determined. Significant differences among herds were detected in the level of sperm activity after 90 minutes of the survival test only, P < 0.05. A significant difference (P < 0.05) between breeds was determined only in the case of sperm activity after 60 minutes of the test. Higher sperm motility during the entire survival test was detected in Bohemia Forest rams. A non-significant difference (P > 0.05) was found in the sperm activity in relation to the age of the rams. Sperm survival during the test significantly differed in relation to sperm density before diluting (P < 0.05). No significant differences among di­lu­ters used were confirmed. Relationships among sperm activity before and after diluting and during the entire survival test were confirmed by significant Pearson´s correlation coefficients (P < 0.001).