Two forms of 0.5% bupivacaine hydrochloride, Anecaine (Pliva) (n = 15) and Marcaine (Astra) (n = 15) were used for epidural anesthesia. The clinical picture of conduction block induced by the two local anesthetics varied. It manifested by a shorter latent period of analgesia development at the level of catheter and the drug infusion (LII) and relatively delayed development of analgesia in peripheral zones for Anecaine in comparison with marcaine. The authors conclude that solutions of local anesthetics containing the same active agent in the same concentrations under different commercial names manufactured by different companies may be characterized by different clinical picture of conduction blockade.