Newly isolated and culture collection strains of Rhodopseudomonas palustris were able to transform phenol to 4-hydroxyphenylacetate under phototrophic conditions in the presence of acetate, malate, benzoate, or cinnamate as growth substrates. The reaction was examined with uniformly C-14-labelled phenol and the product was identified by HPLC retention time, UV-scans, and H-1- and C-13-NMR analysis. The transformation reaction was detectable in cell-free extracts in the presence of NAD+ and acetyl-CoA. For further degradation of 4-hydroxyphenylacetate by R. palustris, low partial pressures of oxygen were essential, presumably for aerobic aromatic ring fission reactions by mono- and di-oxygenases.