Calcium phosphate and chitosan nanoparticles (CaP/Cs NPs) have shown promising potential effects in carriers of antigens in vaccination. However, little is known about the effectiveness of nanoparticle carriers of sonicated whole-cell antigens of Brucella. melitensis (B. melitensis) in biological systems. The purpose of this research is to prepare sonicated whole-cell antigens of B. melitensis loading in Ca P/Chitosan NPs (B.m.As, CaP/CsNPs) by nanoencapsulation method, and examine their physical and chemical characterization by FTIR, X-Ray diffraction and scanning electron microscopy (SEM) techniques. In addition, it verified its safety and could induce a response in the male rats (Wistar strain) using three doses (6,3,1.5) mg/ml respectively. The results showed that the B.mAs, CaP/CsNPs had a significant chemical transformation during the synthesis of B.m.As, Ca, P/Cs nanoparticles, have a soft spherical appearance with diameters (19.43 to 34.34) nm sized homogeneous morphology. Furthermore, XRD analysis showed that the interactions between TPP and chitosan modify the crystalline structure, enhancing polymer chain flexibility. Moreover, the loading rate of B.m.As in Chitosan/CaP nanoparticles was 75%, indicating a highly efficient encapsulation process. On the other hand, redness and thickness decreased significantly (p<0.05) for the three doses respectively after 48 hours, and no mortality was recorded in rats after 14 days of the acute test. In conclusion, loading sonicated whole-cell antigens of B. melitensis in CaP/Cs NPs was safe and promising as active immunogens to induce protection against B. melitensis.