The effects of body size, depth, and sampling scale on spatial heterogeneity were examined in the zooplankton community of a small lake. Analyses were performed by regression analysis of 27 sets (3 scales ° 3 depths ° 3 dates) of replicate (n = 4) samples of the natural zooplankton (cladocerans, copepods, rotifers) community of Lake Cromwell, Quebec, Canada. Spatial heterogeneity was measured as the variance among the four randomly arranged replicate samples of taxa taken at each scale—depth—date combination. The spatial distribution of populations of zooplankton in this community was found to be typical of the spatial heterogeneity encountered in other freshwater and marine ecosystems. The effect of population density on spatial heterogeneity was comparable to that found for other flora and fauna. Small animals were more heterogeneous than large ones, and populations sampled on large spatial scales or at greater depths showed greatest spatial variability. These effects were stable over the season. Few taxa or life stages diverged significantly from these trends.