The effectiveness and tolerance of therapeutic local anesthesia (TLA) with lidocaine was compared with those of oral diclofenac in a controlled, open, randomized study involving 76 patients with gonalgia due to gonarthrosis or patellar chondropathy. During the course of the three-week (maximum) treatment, the summed score of pain at rest, pain on movement, and restricted mobility, taken as the target parameter of effectiveness, decreased significantly more markedly (p = 0.008) under TLA, than under diclofenac. Side effects involving mainly the gastrointestinal tract occurred significantly more frequently in the diclofenac group (p = 0.012). The results of this study indicate that in the treatment of localized joint pain of degenerative genesis, TLA with lidocaine is superior to NSAID treatment in terms of effectiveness and tolerance.