We analyzed pathomorphologic changes of lung interstitium tissue in male Wistar rats (average weight 250300 g, n=20) after single-pass intravenous administration 1ml (2 mg/ml) 13±2 nm silicon dioxide spherical shape nanoparticles. We estimated tissue reaction on 21 st and 60th days after injection. Diffuse infiltration of alveolar partitions increase was noticed (p <0,05); mast cells and eosinocytes pool increase was not significant. We did not revealed granulomas formation or pneumofibrosis. The revealed changes let us to suppose persistence of dispersible silica dioxide nanoparticles in lung interstitium on all terms of study. Cell reaction trends let us to propose that in lungs nanoparticles distribute with local interstitial macrophages.