background: dental caries is a transmissible, infectious, chronic and multifactorial disease; prevails in the infancy and constitutes the fundamental cause of the dental loss. objective: to determine the loss of the first permanent molar tooth in children from 7 to 13 years. method: an observational, descriptive, longitudinal and prospective study was conducted in 63 children from 7 to 13 years belonging to the sector 1 of the urbanization ？las margaritas？, carirubana municipality, falcón state, from september 2005 to may 2006. the studied variables were: age, sex, damage caused to the oral structures and oral hygiene of the boy. results: of the total of patients, 16 correspond to the male sex, what represented the 57.4% of the sample and 12 patients to the female one for a 42.6%. relating to the age a greater number of patients between 10-11 years with a total of six children was obtained (21,4%). the tooth with greater index of absence was the first right lower molar with a total of 16 for the 37.2%. of the most common oral affections caused by the loss of the first permanent molar tooth, was found that 17 children presented extrusion of the antagonist and 13 unilateral mastication. on analyzing the hygiene in the studied children was observed that just in 11 patients (39,2%) was acceptable and in the 60.8% (17 of the patients) were evaluated as no acceptable. conclusions: the male sex was the most affected one by the loss of the first permanent molar tooth and mostly oral hygiene was no acceptable.