The experiment compared the annual dynamics of microclimate parameters in sows and lactation rooms of sows under different variants of their ventilation and its effect on sows' productive qualities and growth of their offspring. Technological group of lactating sows with pigs are very sensitive to any climate change. They are basis for the next development and implementation of their genetic potential, therefore one of the most important issues of retention is the right choice of the microclimate creation system. One of the main tasks in this case is also the reduction of energy costs to ensure proper parameters, both for animals and for their serving staff. It was revealed that during the year the geothermal ventilation system of the premises, due to the heating of the air in the underground mines and its uniform distribution by the air duct system, created more comfortable temperature conditions of keeping for the pigs and sows, compared to the traditional ventilation system. Both traditional and geothermal ventilation systems during this period provided optimal gas composition of the air and maintained it within the normal range. Optimal indices of humidity in rooms were at both systems of creation of a microclimate in all seasons except summer. In the summer both ventilation systems failed to provide optimal indoor humidity. The best microclimate conditions created by the geothermal ventilation system in the pig yard for the farrowing contributed to the improvement the conservation of piglets by 1.05−2.03 % before weaning, the increase in individual weight by 2.87−9.83 %, nest weights by 3.82−11.57 % when weaned, and live weight gain of suckling piglets by 8.12−25.9 g in all seasons, compared to the traditional system. Key words: productivity, ventilation, microclimate, air, temperature, gas composition, sow, piglet, multiplicity.