The mean number of embryos in 134 prairie voles was 3.89 with a range of 2 to 7. Corresponding values in 153 eastern voles were 4.46 and 1 to 9. The mode was four in both species. An estimated 89.4% and 93.0% of the ova liberated were implanted in the prairie voles and the eastern voles, respectively. Prairie voles breed throughout the year at Terre Haute, Indiana. Pregnant eastern voles were taken in all months but January. The percentage of pregnant females was lowest in the winter and highest in the spring for both species. There was no significant difference between the mean number of young per litter produced in captivity and the mean number of embryos in the uteri of either species. Placental scars disappeared at about 42 to 45 days in the prairie vole and in about 44 to 49 days in the eastern vole.