The 5-day BODs of 45 organic chemicals were determined using acclimated mixed microbial cultures. These chemicals included alcohols, acids, esters, ketones, aromatics and miscellaneous compounds. The BOD data were correlated with water solubilities, log of l-octanol/water partition coefficients, molar refractivities and volumes, melting (m.p.) and boiling points, number of carbon (C No.), hydrogen and oxygen atoms, molecular weights, and theoretical (Th) BODs of chemicals. Linear and second-order polynomial regression analyses were used; the latter was also attempted with two or more independent variables. All prediction equations were compared for statistical merits. The acclimation potential of an autochthonous microbial community cannot yet be predicted, but the study demonstrates that the process of active biodegradation for structurally dissimilar chemicals appears to correlate quantitatively with certain physiochemical parameters. (Copyright (c) 1987 Society for Industrial Microbiology.)