A mixed culture was enriched with a mixture containing bromobenzene, chlorobenzene, fluorobenzene, and iodobenzene. The culture was initially selected for growth at the expense of chlorobenzene as the sole source of carbon and energy. None of the halogenated compounds was detected in the growth medium after three weeks of continuous operation in a stirred tank bioreactor. The complete mineralization of each of the compounds with concomitant release of stoichiometric amounts of halide was then investigated individually in batch experiments. Mineralization of chlorobenzene, bromobenzene, and iodobenzene up to their maximum solubility level in minimal salts media was achieved. Fluorobenzene simply volatilized instead of biodegrading. A search of published literature shows no previous report of the complete mineralization of iodobenzene with complete recovery of iodide. Strains of Pseudomonas putida have been identified in preliminary characterization of the cultures responsible for iodobenzene and bromobenzene biodegradation.