This work, during a period of 2 years, has been carried out on 139 brachial plexus block anesthesias out of which --92 through axillary approach--47 through supraclavicular approach. Our failure rate was--6,5 p. cent in the case of the axillary block--10,6 p. cent in the case of the supraclavicular block. This gives us a failure average of 7,9 p. cent. Depending on the duration of the operation we have been using three kinds of drugs, always without adrelanine--Lidocaïne . . . 2 p. cent--Mepivacaïne . . . 2 p. cent--Bupivacaïne . . . 0,5 p. cent. We finally adopted two mixtures based on lidocaïne together with mepivacaine or bupivacaine keeping the same concentration but reducing to half the doses of these last two drugs. In our work, we have not noted any complication, and we think that a locoregional anesthesia, should, as far as it is possible, be used as a substitute for general anesthesia instead of being used when general anesthesia is contra-indicated.