Brazil has a high diversity of fruit due to different climatic and edaphic conditions. Among the Brazilian native fruit species, the custard apple stands out because it is an exotic fruit, very perishable and seasonal, with specific characteristics, mainly consumed in natura. This fruit has many seeds. Considering its high consumption in the North region, this study aimed at the physicochemical characterization of custard apple seed, commercialized in the municipality of Paraíso do Tocantins, Tocantins State, Brazil. The seeds were obtained from fruit harvested from three trees, in the surroundings of the mentioned municipality. The experiment was carried out in the Laboratory of Biomolecules Separation and Food Dehydration Processes at the Federal University of Tocantins. From the samples of custard apple seed, the following determinations were performed: moisture, ashes, and lipids, according to the ADOLFO LUTZ INSTITUTE methodology, and the protein was determined by the Kjeldahl method. The results obtained from the determinations were 7.48%, 2.89%, 7.93% and 16.12%, for moisture, ashes, lipids, and protein, respectively. From this research, it was observed that the physicochemical parameters determined here indicated that the custard apple seed is within the nutritional parameters for a diet rich in lipids.