Objective: To determine the concentration of fluorine ppm in toothpastes for children that are commercialized in Lima Peru in the year 2017. Material y Methods: It is an observational, descriptive, cross-sectional study. 48 pediatric toothpastes sold in pharmaceutical establishments (pharmacies and drugstores) in Lima were collected. The Student t and Wilcoxon t tests were used for a single sample. Results: The difference between the concen-tration of fluorine as labeled and found in Colgate of 1 100 ppm was -119.8 ppm (median), Oral B of 500 ppm was -57.05 ppm (median). The difference between the concentration of fluorine according to labeling and that found based on the average was Colgate of 500 ppm: -34.2 ppm, Farmadent of 452 ppm: -36.27 ppm, Dentito of 550 ppm: -520.1 ppm, Aqua fresh of 500 ppm: +41.67 ppm, Vitis of 1 000 ppm: +141.85 ppm, Aqua Fresh of 1...