Aim. We sought to assess the effects of exogenous Hsp70 (single subcutaneous low- and high-dose injections) on organ structure and functions in adult mice.Materials and methods. We randomized CD1 90-day-old male mice (n = 30) to three groups (10 mice per group). We injected the animals with single subcutaneous saline solution for Group 1 (control), low dose (500 μg/kg) of recombinant human Hsp70 (HspA1A) for Group 2, and high dose (5000 μg/kg) of the Hsp70 for Group 3. We examined the behavior of the mice on Day 3 after the injections (distance traveled, velocity, and bowel movement number). We lethalized the mice on Day 5 with further histological study and morphometrics of cerebral cortex, thymus, spleen, and liver. The statistics included one-factor ANOVA test with post hoc Tukey test.Results. All study groups exhibited no significant difference of behavioral parameters. Some liver sinusoids were wider in control group and Hsp70 500 μg/kg group comparing to Hsp70 5000 μg/kg group. We obtained also data for morphometrics: no difference was found for the number of neurons in ganglionic cerebral cortex, the lymphocytic cellularity difference between thymic cortex and medulla, the number of lymphocytes in white splenic pulp, and the number of hepatocyte nuclei in the liver. Red splenic pulp exhibited 1774,5 ± 24,8, 1623,0 ± 26,7, 1553,6 ± 47,0 macrophages for control, low-dose and high-dose groups, respectively (р < 0,0001). Tukey test showed a significant difference between control group and each of Hsp70 groups 500 μg/kg (р = 0,012) and 5000 μg/kg (р < 0,0001).Conclusion. Our study revealed no negative impact of subcutaneous Hsp70 administration at low and high doses on organ structure and functions in mice.