Fluoride has been the most important preventive method on development of the caries. This in vivo study evaluated the effects of lowintensity red laser radiation on the fluoride uptake in enamel. Ten healthy participants were recruited for this study. The two upper central incisors of each volunteer were used and divided into 4 groups: group GC (control), which was untreated; group GF (fluoride), which received topical acidulated phosphate fluoride (APF) 1,23% treatment for 4 minutes; group GLF (laser + fluoride), which was irradiated with a low-intensity diode laser (l= 660 nm and dose= 6 J/cm??) with APF application after irradiation and group GFL (fluoride + laser), which received APF before irradiation using the same parameters as GLF. The determination of fluoride was performed using a fluoride ion electrode after an acid-etch enamel biopsy. The results showed a significant increase of the fluoride uptake in enamel for groups GF, GLF and GFL when compared to control group. Although a percentage increase of 57% was observed for GLF with respect to GF, there were no statistical differences among the treated groups. These findings motivate further studies in order to introduce low-power laser associated to APF as a protective method of dental caries.