The present invention is directed to methods of treating movement disorders by administering an effective amount of one or more adenosine A2A receptor antagonists to a patient in need thereof. The present invention also provides methods of decreasing the adverse effects of L-DOPA in patients receiving L-DOPA therapy in the treatment of Parkinson's disease. The present invention further provides methods and compositions for treating Parkinson's disease patients with sub-clinically effective doses of L-DOPA by combining L-DOPA treatment with an effective amount of one or more adenosine A2A receptor antagonists (i.e., L-DOPA sparing effect). The present invention further provides methods of effective treatment of Parkinson's disease by co-administering at least one adenosine A2A receptor antagonist, L-DOPA and a dopamine agonist and/or a COMT inhibitor and/or a MAO inhibitor. The present invention further provides methods of prolonging effective treatment of Parkinson's disease by administering an adenosine A2A receptor antagonist singly or together with a dopamine agonist, and/or a COMT inhibitor, and/or a MAO inhibitor without prior or subsequent administration of L-DOPA, delaying or removing on-set of L-DOPA motor complication.