Neutron activation analysis was applied to the determination of theelements Al, As, Ba, Br, Cl, Co, Cr, Fe, K, Mg, Mn, Mo, Na, Rb, Sb, Sc, Ti,Th, V, Zn, and the rare earths La, Ce, Nd, Sm, Eu, Tb and Yb in the epiphyticbromeliad Tillandsia usneoides. The samples were collected at an unpollutedarea and exposed in different sites of the city of So Paulo, Brazil,and in a control site outside S
o Paulo. The results obtained showedan accumulation of Al, As, Cr, Fe, Mo, Sb, Ti, V and Zn elements in Tillandsiausneoides exposed in polluted sites, indicating a promising potential of thisspecies as a biomonitor of air pollution in S
o Paulo.