Abstract Biodegradabilities of surfactants in four detergents namely SDS, Teepol, Apollo, Spencer and Triton X-100, and two shampoos, Flex and Rainbow, were assessed using the river-water die-away method. The shampoos underwent a more rapid primary biodegradation than the liquid detergents. The ease of degradation over a 12-day period followed the order—SDS (97%), Rainbow (85%), Flex (79%), Spencer (79%), Apollo (77%), Triton X-100 (63%) and Teepol (59%) and appears to be related to their sulphate concentrations. A microbial consortium comprising the following genera— Vibrio, Flavobacterium, Klebsiella, Pseudomonas, Enterobacter, Bacillus, Escherichia, Shigella, Citobacter, Proteus and Anaebena—were found to effect the degradation. The detergents and shampoos supported microbial growth in the following decreasing order; Teepol, Spencer, Flex, Rainbow, Apollo and Triton X-100. It is concluded that the detergent or shampoo that supports the most microbial growth is not necessarily the most easily degraded.