Cottontail rabbits (Sylvilagus floridanus) were collected to determine whether soils of contrasting fertility in small areas can cause variation in the size of cottontail litters. Relative fertilities of three soil series in Stoddard County in southeastern Missouri were rated. Rabbits from these soils were collected (with due consideration of home range) and the reproductive tracts of females pregnant with their first litter of the breeding season were used in testing for inter-soil differences in reproduction. Rabbits from the most fertile soil (Sharkey) had significantly larger litters than those from the least fertile (Calhoun). Analyses indicate that the observed difference in fecundity was the result of the contrast in soil fertility rather than differences in latitude, age of the mother, or stress. Anatomical materials were analyzed chemically to detect deficient mineral elements that might account for differences in rabbit fecundity. The concentrations of manganese in the liver, and calcium and phosphorus in the teeth did not differ significantly for collections from the two soils.