Gangliosides, defined as sialic acid-containing glycolipids, are abundantly distributed on the surface of must neurones. Previous reports have demonstrated that pretreatment with gangliosides accelerates adaptative changes in different neuronal system induced for several pharmacological treatments. Since central dopaminergic system is critically involved in reward mechanism, using an unbiased place conditioning procedure, we have analyzed the influence of exogenous GM1 ganglioside on cocaine induced conditioned rewarding effects and behavioral sensitization. The place conditioning produced by cocaine (5 or 10 mg/kg) was assessed after 1 to 4 conditioning session with the drug. GM1 acutely administrated 2 hours before cocaine (5 mg/kg) induced conditioning effect after 4 conditioning sessions, and when GM1 is administrated before cocaine (10 mg/kg) this effects was evident after 2 and 3 conditioning sessions, any conditioning place preference was observed after 4 sessions. Moreover, pretreatment with GM1 (30 mg/kg 2 hours before cocaine 10 mg/kg, twice a day during 5 days. This results suggest that GM1 ganglioside plays an important role in the events related to dopaminergic plasticity and increases the rewarding properties of cocaine since it decreased the effective dose of cocaine necessary to induce conditioned place preference as well as the number of conditioning sessions.