Seasonal means of chlorophyll (Chl), total phosphorus (TP), total and non-volatile suspended solids (TSS, NVSS), and Secchi depth from 28 reservoirs and natural lakes in Iowa, Kansas, and Oklahoma were used to test predictions of log-log regression models developed from Missouri reservoirs by Jones and Knowlton (1993). Water-bodies in Iowa, Kansas, and Oklahoma exhibited a curvilinear relation between log-Chl and log-TP similar to that for Missouri reservoirs. These data fit the Missouri regressions for Chl-TP and Chl-(TP NVSS) fairly well; although the Missouri models usually underpredicted Chl for Iowa waterbodies. Missouri models provided an excellent fit to outstate transparency data.