We present a prospective study of 240 patients with medication overuse headache (MOH) treated with drug withdrawal and prophylactic medications. At 1-year follow-up, 137 (57.1%) patients were without chronic headache and without medication overuse, eight (3.3%) patients did not improve after withdrawal and 95 (39.6%) relapsed developing recurrent overuse. Age at time of MOH diagnosis, regular use of benzodiazepines, frequency and Migraine Disability Assessment (MIDAS) score of chronic headache, age at onset of primary headache, frequency and MIDAS score of primary headache, ergotamine compound overuse and daily drug intake were significantly different between successfully and unsuccessfully treated patients. Multivariate analysis determined the frequency of primary headache disorder, ergotamine overuse and disability of chronic headache estimated by MIDAS as independent predictors of treatment efficacy at 1-year follow-up.