Thermochemical treatment by acid gases, which takes place during the process of glassware production, is a simple method to improve the physical and chemical properties of glass [1-2]. Chemical resistance of glass containers is significantly increased when processed with fluorine– and chlorine–containing gaseous reagents [1, 3]. The aim of the undertaken experiments was to investigate the effect of thermochemical treatment by fluorine– and chlorine–containing gaseous reagents on microhardness of container colorless glass. Objects of investigation were jars, bottles and flasks of colorless glass. Difluorodichloromethane and difluorochloromethane were used as gaseous reagents. Thermochemical treatment of glass samples was held in laboratory and industrial conditions. The main regimes of thermochemical treatment of glass samples in laboratory conditions are: temperature - between 20 and 700 oС, duration - between 1 s and 2 h, quantity of gaseous reagent introduced into the reacting vessel - between 0.01 and 1.00 mol. The main industrial conditions of treatment of glassware by gaseous media are: temperature – between 500 and 800 °C, duration of reagent feed - 1 s, volume fraction of gaseous reagent (gaseous reagent volume vs. container capacity) between 0.1 and 20.0 %.   Microhardness of glass was determined by the microhardnessmeter PMT-3M. The method of microhardness measuring was the following. Each sample was pricked by diamond pyramid about 20 times. In order to obtain reproducible results the duration of loading on the pyramid was 10 s and duration of exposition on glass - 10 s for every measurement. The indentation length was measured twice. The load on the indenter of the diamond pyramid Vickers was 0.2 N. The relative error of determination of microhardness did not exceed ±5 %. The changes in value of microhardness of glass were tested in these experiments in comparison with the property of initial non-treated samples (only after heating). The data obtained were analyzed by the computer program of statistics calculations which has especially been developed for the given task.   Increasing water resistance of glassware by thermochemical treatment with fluorine– and chlorine– containing gaseous reagents was achieved by two fundamentally different regimes. In the first case, the volume fraction of gaseous reagent from the total capacity of the glassware accounted for more than 0.3 %. This treatment led to the formation of intensive white bloom on the glass surface, which indicated that the dealkalization was in its process. Water resistance of glass in this case improved by several times and the microhardness increased by 10-15 %. A significant improvement of water resistance of glass was achieved after the second regime of treatment, when the volume fraction of fluorine– and chlorine–containing gaseous reagent ranged from 0.05 to 0.2 %. The above mentioned regimes of treatment led to the formation of barely visible bloom on the internal surface of glassware (or it might be absent in general) and did not change the microhardness of glassware.   The study discusses the possible mechanism of chemical interaction of container colorless glass with fluorine– and chlorine–containing gaseous reagents in laboratory and industrial conditions.