Prilocaine (PLC) and mepivacaine (MVC) are aminoamide local anesthetics widely used in regional anesthesia. We have previously reported the preparation and characterization of 3% liposomal PLC (PLC_LUV) and 2% liposomal MVC (MVC_LUV) formulations; both inducing enhanced analgesic effects when compared to their aqueous solutions at equivalent concentrations (Cereda et al., J. Pharm. Pharmac. Sci. 7:235, 2004; Araujo et al, Can. J. Anesth.51:566, 2004). In view of the fact that these formulations can be clinically used in the future, we have decided to investigate their toxicity. Firstly, the cell culture test was used to assess in vitro toxicity in our laboratory. In the present work, we report the in vivo local toxicity evaluation of these formulations using the paw-edema test. Male Wistar rats (250-350g, n= 6) were used in the groups: saline, Hepes buffer, liposomes_{local anesthetic-free,} plain anesthetic solutions and liposomal formulations, for each of the anesthetic studied: PLC or MVC. Before the test, the animals were anesthetized with thiopental by intraperitoneal route (40mg/kg). Later, the baseline volume of the animal paw was measured and intraplantar injections (0.1 mL) of the test solutions were given in the right paw. The paw volume measurement was obtained with a plethysmometer (Ugo Basile) at 60, 120 and 180 min after injection. PLC_LUV and MVC_LUV did not evoke rat paw edema when compared to the control groups: saline, Hepes buffer, PLC in solution, MVC in solution and Liposomes_{local anesthetic-free} (p > 0.05). Our results led to the conclusion that the liposomal formulations studied (PLC_LUV and MVC_LUV) did not induce inflammatory effects on rat paw. Other in vivo experiments are being conducted in our group to discard any kind of toxic effect of these liposomal formulations, allowing for their clinical use in the future. Supported by CAPES, CNPq and FAPESP.