In a recent paper, Kats et al. (2000) reported three experiments intended to test for effects of UV-B radiation (hereafter, UV-B) on predator-avoidance behaviors in three amphibian species. They introduced their study in the context of concern about increasing penetration of solar UV-B to ground level, owing to loss of stratospheric ozone, and its possible effects on amphibian populations. Kats et al. concluded from their results: `ultraviolet exposure may have important sub-lethal effects in amphibians that could adversely effect (sic) their fitness'. As Kats et al. cited field studies that apparently demonstrated lethal effects of ambient levels of UV-B on amphibians, their conclusion that sub-lethal effects may occur is not obviously contentious. Furthermore, their experiments appear to be based on accepted methods. Nevertheless, I contend that the conclusions drawn by Kats et al. are not justified by the results they reported. Here, I discuss some problems with their study and suggest some possible improvements for future studies.