In this study, the anticancer drug letrozole (LTZ) was formulated using chitosan nanoparticles (CS-NPs) with the crosslinking agent sodium tripolyphosphate (TPP). The nano-formulation was optimized by varying the concentration of drug. The prepared particles were characterized using FTIR, TGA, XRD, SEM, TEM and DLS. From the FTIR results, the appearance of a new peak for double bond; length as m-dashCsingle bondH, Cdouble bond; length as m-dashC and Cdouble bond; length as m-dashN confirms the formation of LTZ loaded chitosan nanoparticles. TEM images shows that the average particle size was in the range of 60–80 nm and 20–40 mm air dried and freeze dried samples respectively. Also the prepared formulation had been evaluated in vitro for determining its hemocompatability, biodegradability and serum stability. The preliminary studies supported that the chitosan nanoparticles formulation has biocompatibility and hemocompatible properties and it can act as an effective pharmaceutical excipient for letrozole.