Very few studies have examined the effect of religiosity on fertility at the macro level. This note extends these studies by using a larger data set and more advanced econometric techniques. In addition, this note estimates the macro-level effect of religiosity on fertility both for a total sample of 25 Christian countries between 1925 and 2000 and for three subsamples: Catholic, Protestant, and mixed Catholic-Protestant countries. Results show that religiosity, in general, has a positive long-run effect on fertility. However, this effect is not significant for Catholic countries.