ABSTRACT: We studied the clinical and genetic characteristics of 100 patients with definite diagnosis of essential tremor (ET), evaluated at the clinic of movement disorders of the National Institute of Neurology of Mexico. All patients hab laboratory (metabolic and endocrine tests), neurophysiologic studies, and neuroimaging studies to evaluate the presence of other potential causes of movement disorders. The study included 100 patients with definitive diagnosis of ET, 33 men and 67 women. The mean age at the time of diagnosis was 45,92 years (40.92 in men and 48.4 in women). Mean time from the onset of tremor to diagnosis was 10.60 years (13,71 in males and 9.07 in females). Family history of tremor was found in 56% of the patients. Patients with maternal inheritance had lower age of onset (35.61 years vs. 46.11 years, p<0.05). Five percent of the patients exhibited almost a total lack of capacity in writing and in fine and precise activities. This study showed that patients with ET inherited frim the mother exhibit a lower age of onset. A narrow relationship between the sex of the progenitor and ET probably exists, The torpid evolution of the tremor was noted in 5% of the cases, emphasizing the need for early therapy before deterioration becomes incapacitating.