Cryoprotectants enable the long-term storage of biomaterials. Despite progress in cryopreservation, there are a number of problems associated with damage to the cell membranes that result from insufficient efficacy and toxicity of some components. In this regard, it is important to develop non-toxic cryopreservation agents performing well at low temperature. The study was aimed to assess morphofunctional features of blood cells in the lactulose-based cryopreservation agent considering the effects of moderate low temperature (–40 °С). Blood cells (leukocytes, erythrocytes, platelets) collected from 30 conditionally healthy female voluntary donors aged 18–23 years were assessed. The complete blood count test was performed using the Gemalight 1270 automated hematology analyzer. Computerized cytomorphometric assessement was performed using the MECOS-C2 hardware and software complex. The study results showed morphological and functional integrity of blood cells after the 24 h storage at the temperature of–40 °С when added the lactulose-based cryopreservation agent developed: erythrocytes — 85.3 ± 0.30 % (p < 0.05), platelets – 75 ± 0.71 % (p < 0.05), leukocytes – 90.1 ± 0.91% (p < 0.05) of the values reported before freezing. The findings demonstrate the potential of using lactulose as a non-toxic component of cryopreservation systems, which will expand the range of cryopreservation agents used and make it possible to analyze morphofunctional parameters of frozen whole blood samples when conducting large-scale studies.