Aim: The present study designed to evaluate the toxic effect of anatase TiO2 NPs on BALF biochemical changes and liver alteration in rats. Background: titanium dioxide (TiO2) nanoparticles (NPs) are utilized in food color additives and cosmetics worldwide. Humans uptake these nanoparticulate by different routes and may exhibit potential side effects, lags behind the rapid development of nanotechnology. Methods: Sixty-three mats rats were used. Included by the control group and the experimental groups treated twice a week with 0. 5, 5, 50, 1. 5, 15, 150 mg/kg of nano-TiO2 (size 21 nm), for four consecutive weeks. Animals were sacrificed at 4 days, a month and three months post-instillation. The levels of tumor necrosis factor-α (TNF-α ) and macrophage inflammatory protein-2 (MIP-2) were measured in the lung homogenate and in the bronchoalveolar lavage fluid (BALF) supernatants by enzyme-linked immunosorbent assay (ELISA) and histopathological examination of liver tissue was performed. Results: The results showed that TiO2 NP induces many alterations in the liver structure after 4 days, a month and reduced after 3 months from intratracheal instillation. This included liver heavy infiltration of inflammatory cells, an increase of collagen density in portal triads, beginning of fibrosis formation and Glisson capsule thickness increase and TiO2 NPs reached the liver tissue after a month from exposure at all doses especially low doses (0. 5, 1. 5, 5) mg/kg of TiO2 NPs. Conclusion: The immune system was strongly responded in the groups treated with high doses (15, 50, 150) mg/kg of TiO2 NP leading to raising the concentration of α-TNF, and MIP-2 in BALF while they decrease in tissue homogenate.