Recent studies reported the development of protein-based nanoparticles by the use of ɣ-irradiation for the production of advanced drug carriers and biomaterials at nanolevel. Basically, the technique combines protein aggregation by means of protein desolvation using a cosolvent, followed by crosslinking using irradiation. We hereby report the effect irradiation dose over the development of protein-based nanoparticles combined or not with cosolvents. BSA was used as a model protein and the samples were irradiated in phosphate buffer (pH=7.2) using a gammacell in absence or presence of ethanol or methanol at 30% and 40% (v/v) respectively. The irradiation dose effect was evaluated following the exposition of BSA to 2.5, 5, 7.5 and 10 kGy over particle size and protein crosslinking, as determined by photon correlation microscopy and fluorescence measurements. Optimized effects were achieved at 10 kGy, under the assayed dose range, with regard to higher particle size and protein crosslinking levels. The use of irradiation was suitable for the synthesis of BSA nanoparticles and tuning of particle size was achieved by controlling the absorbed dose. While the use of ethanol provided an additional control over BSA particle size if compared to the use of methanol at the concentrations assayed, the possibility to perform BSA crosslinking in absence of cosolvents unraveled a novel one-step procedure for the synthesis of protein nanoparticles with no toxicity generated by the use of cosolvents or monomers.