The effects of tumescent solutions consisting of lidocaine and epinephrine on skin flap survival in rats were studied. Dorsal skin flaps of rats were infiltrated using lidocaine (1%) with epinephrine in concentrations of 1:100,000, 1:200,000, 1:400,000, and 1:800,000 prior to elevating flaps of the different experimental groups. The solutions were applied intradermally or subcutaneously, and the flaps were raised “immediately” or “delayed” after injection in the different groups. Control flaps were infiltrated by lidocaine (1%) only. The survival of the flaps was assessed on the seventh day after the operation. As a result, the flaps showed higher necrosis rates in the groups injected by lidocaine with epinephrine in concentration of 1:100,000 and 1:200,000 than of the other experimental or all control groups (P < 0.01). In conclusion, lidocaine with epinephrine in concentrations of 1:400,000 and 1:800,000 was found safe on skin flap survival for tumescent technique in rats.