Studies have shown the cariostatic effect of Er,Cr:YSGG (2.78 mm) laser irradiation on human enamel and have suggested its use on caries prevention. However there are still no reports on the intrapulpal temperature increase during enamel irradiation using parameters for caries prevention. The aim of this in vitro study was to evaluate the temperature variation in the pulp chamber during human enamel irradiation with Er,Cr:YSGG laser at different energy densities. Fifteen enamel blocks obtained from third molars (3 x 3 x 3 mm) were randomly assigned to 3 groups (n=5): G1--Er,Cr:YSGG laser 0.25 W, 20 Hz, 2.84 J/cm(2), G2--Er,Cr:YSGG laser 0.50 W, 20 Hz, 5.68 J/cm(2), G3--Er,Cr:YSGG laser 0.75 W, 20 Hz, 8.52 J/cm(2). During enamel irradiation, two thermocouples were fixed in the inner surface of the specimens and a thermal conducting paste was used. One-way ANOVA did not show statistically significant difference among the experimental groups (alpha=0.05). There was intrapulpal temperature variation < or = 0.1 degrees C for all irradiation parameters. In conclusion, under the tested conditions, the use of Er,Cr:YSGG laser with parameters set for caries prevention lead to an acceptable temperature increase in the pulp chamber.