The study of the local indexes of reactivity Fukui on indol-3-carboxaldehyde, benzaldehyde and formaldehyde was carried out with the computational package Gaussian98 at B3LYP/6-31g(d) level of theory by the (DFT). The results demonstrated that the site more nucleophilic and electrophilic of indol-3-carboxaldehido differs with relation to the aldehydes previously mentioned.