Nanoparticles can be produced from the proteinaceous materials called gelatin. Gelatin is extracted from collagen of skin, bones, and connective tissues by controlled acidic or basic hydrolysis. This paper focuses on several methods developed for preparing and modifying gelatin nano-particles (GNPs) for delivery of gene and drugs. In general, eight methods are being used for producing GNPs: the coacervation method; the two step desolvation method; the complex coacervation process; the solvent extraction or emulsion process; the nanoprecipitation method; the microemulsion method; the inverse miniemulsion technique and self-assembly method. The problem of being phagocytosized by the mononuclear phagocyte system (MPS) in the body is among the limitations of native GNPs encounter. The interest was based on the facts that gelatin has been known for its low immunogenicity for many years and is administered intravenously since it is an ingredient of various registered blood substitutes. The advantage offered by the amino acid side-chains of the gelatin matrix molecule is the option of multiple further modifications. Hence, GNPs’ surface modification is typically needed to tackle phagocytosis. Many researchers have reported the gelatin use for anticancer drugs delivery, gene delivery, pulmonary drug delivery, ocular drug delivery and protein delivery.