Little is known about the reproductive habits of the 4 species of bat in the genus Lasiurus that live in Louisiana. We examined reproductive notes from specimen records for the eastern red bat (L. borealis), the Seminole bat (L. seminolus), the northern yellow bat (L. intermedius), and the hoary bat (L. cinereus). We found that gestation and partuition happen between May and June for all species. Lactating and postlactating individuals and juveniles were mostly captured in late June or July. Typically, litter sizes range from 3 to 4 pups for both L. borealis and L. intermedius and from 1 to 3 pups for L. seminolus. Males for all species became scrotal in early fall between August and October, suggesting that fertilization is delayed till the spring. However, we do provide evidence that copulation may also occur in early spring for L. intermedius.