Abstract : N-nitrosodimethylamine (NDMA) is biodegraded by microorganisms under certain conditions. In batch aqueous and soil studies the initial rates of mineralization increase with increasing concentration of NDMA, (ppt to ppm) however, the total percent or extent of mineralization decreases with increasing initial concentration. We were unable to demonstrate significant rates of biodegradation in continuous culture systems under anaerobic or aerobic conditions with a range of concentrations of NDMA. These limits on biodegradability indicate that a biological treatment mode, with the exception of a laboratory scale trickling filter containing activated charcoal, may not be a feasible alternative to deal with NDMA-laden wastewaters. The granular activated charcoal filter system demonstrated an ability to mineralize NDMA at feed concentrations of 50 ppm and 100 ppm. This system appears to warrant further investigation or scaleup for potential applicability for biological treatment of NDMA contaminated waters. Formaldehyde and methylamine were identified as transitory intermediates formed during the biodegradation of NDMA.