Different metals are increasingly used to manufacture implants, especially in the field of dentistry. Metallic implants of titanium are used therapeutically in biomedicine because of their high corrosion resistance and excellent biocompatibility when compared to more conventional stainless steels and cobalt-based alloys. However, no metal or alloy is completely inert. Thus the aim of the present study was to determine the histopathological and immuno-histochemical effects in some target organs of adult male albino rats induced by titanium exposure. This work was carried out on two groups: control group which included 10 rats and treated group which included 20 rats that received intraperitoneal injection of suspension of titanium dioxide (TiO₂) in a dose of 150 mg/kg body weight (BW) per day for 45 days. Samples of liver, spleen, kidney, and lung were processed for histological examination. Cryostat sections of spleen samples from each group were stained with common lymphocytic antigen (CLA) for lymphocyte detection. Results revealed histopathological changes in the liver, spleen, lung and kidney of the treated group. The CLA staining of the spleen in the treated group revealed toxic alteration within the spleen, indicating that the immune system may be affected and so interfering in the body defense mechanism.