This work presents a study QSAR among the MAO A inhibitory activity (IMAO A) of a xanthones series correlated with descriptors like the E-state index (S(i)), molecular connectivity (chi) and shape (k) descriptors. The xanthones group (9-H-xanton-9-onas) are of natural or synthetic origin, they present eight positions for the substitution and their MAO A inhibitory activity is reported in the work from Gnerre et al. The descriptors included in the adjusted model were selected to describe the molecular structure of the compounds. The model was selected using the leave-one-out method, the cross-validation statistics indicate a model useful for prediction: r(2)=0.847 and s=8.069, calculated by multiple linear regression.