Pachymerus nucleorum (Fabricius, 1792) is a beetle species of the Bruchinae sub-family, family Chysomelidae, whose principal host is the babassu palm (Orbinya spp). The objective of this work was to identify and characterize the ATPase activities in P. nucleorum larvae. The P. nucleorum larvae guts were discarded and the greasy bodies were homogenized in 50 mM Imidazole buffer (pH 7,5) containing protease inhibitors (0,2 mg/mL Aprotinine, 1 mM Benzamidine), 250 mM sucrose and 1 mM EDTA, and then centrifuged at 15000_xg for 30 minutes, 4 º C. The S1 fraction was treated with ammonium sulfate 20% and centrifuged at 45.000_xg for 30 minutes at 4 º C. The precipitated fraction (P2) was re-suspended in Imidazole buffer (pH 8,0) containing 1 mM EDTA, 0,2 mM b-mercaptoetanol and then centrifuged at 45.000_xg for 30 minutes at 4 º C. The resulting precipitate (P3 fraction) was re-suspended in Imidazole buffer, pH 8,0 containing 10 mM ATP and 5 mM MgCl₂ and centrifuged at 45.000_xg for 30 minutes at 4° C, resulting in the P4 precipitate (ATPase fraction). The ATPase activity was measured by quantifying the inorganic orthophosphate released during the hydrolysis reaction of the substrate. The P4 fraction presented high Mg²⁺-, Ca²⁺- and Co²⁺-ATPase activities while K/EDTA-ATPase activity was absent. The activity was maximal in magnesium 1,5 mM. At lowest magnesium concentrations, calcium or cobalt stimulated the Mg²⁺-ATPase activity, but above this point, these cations did not stimulate the Mg²⁺-ATPase, suggesting that only one ATPase was responsible for the Mg²⁺-, Ca²⁺- and Co²⁺-ATPase activities. The main polypeptides of this fraction presented Mr of 180, 54, 43 and 17 kDa in SDS-PAGE. The Mg²⁺-ATPase was slightly inhibited by vanadate, and the Mg²⁺-GTPase activity was about 50% of Mg²⁺-ATPase activity. In this study we obtained an ATPase-rich activity fraction from Pachymerus nucleorum larvae greasy bodies free of the digestive system, and the ATPase activity was partially characterized.