Villin-Cre shows maximal activity between E14.5-E15.5. Villin-Cre (Tg(Vil-cre)997Gum) and Rosa26R mice (Gt(ROSA)26Sortm1Sor) were crossed to determine Cre activity. Embryonic small intestine harvested at E13.5, E14.5, and E15.5 was stained for β-galactosidase activity (blue staining) to identify Cre activity. At E13.5, minimal Cre activity was detected in jejunum and ileum (n = 9 Cre + embryos from 2 litters; 5/9 showed scattered blue cells; 4/9 had no blue cells). At E14.5, two types of staining were detected (n = 11 Cre + embryos from 2 litters). One group (4/11) had heterogeneous staining in jejunum and ileum (E14.5 left panel). The other group (7/11) had robust homogeneous staining in jejunum and ileum (E14.5 right panel). At E15.5, we observed 3/4 Cre + embryos with robust homogeneous staining in jejunum and ileum. One Cre + embryo had a low level of blue staining reminiscent of earlier stages (n = 4 Cre + embryos from 1 litter). Scale bars, 50 μm.