Catechol 1,2-dioxygenase was purified from cells of R. rhodochrous N75 grown at the expense of benzoate and p-toluate as the sole sources of carbon. A single catechol 1,2-dioxygenase was found to be induced with either growth substrate. The enzyme has an estimated $M_r$ of 71,000 consisting of two identical subunits. Catechol 1,2-dioxygenase from R. rhodochrous N75 exhibits some unusual properties including: broad substrate specificity, extradiol cleavage activity with 4-methylcatechol and low $K_m$ values for halocatechols, suggesting that this enzyme is distinct from other known catechol and chlorocatechol 1,2-dioxygenases.