A process for obtaining biopolymeric nanoparticles containing Azadirachta indica A. Juss (Neem) is described, which comprises, in Phase I, in (10), preparing an aqueous emulsion of Neem oil and extracts, in Phase II, in (20), preparing a biopolymer solution in organic solvent, followed by mixture of both Phases I and II, and, in Phase III, in (30), preparing an aqueous emulsion of a surfactant and adding it to the Phase I and II mixture, affording a nanoparticle suspension which is stabilized. Biopolymeric nanoparticles and powder microparticles obtained are also described.