Zinc oxide (ZnO) crystals have recently drawn attention due to a relatively low price and to their application perspectives in optoelectronics. One of the most cheap and simpler methods for obtaining such crystals with controllable electrical parameters and impurity composition varied in a wide range is the chemical vapor transport (CVT) in sealed chambers. The thermodynamic analysis and experimental data for the use of HCl as a chemical vapor transport agent (TA) for ZnO single crystals growth were demonstrated earlier [1]. High density of products for HCl+ZnO interaction, that is favorably for high quality of grown crystals, as well as low temperature dependence of the product densities limiting the rate of ZnO mass transport have been shown. Recently, new method of using HCl+H2 gas mixture was suggested for ZnO single crystal growth [2]. Additional presence of H2 increases of the mass transport rate by 4-7 times up to 1.5 mm per day, minimizes the wall adhesion effect and the deformation of crystals. Disadvantage of the proposed method is fast diffusion of H2 through growth chamber walls and necessity of continuous hydrogen supply. In this regard, great interest is the elaboration of alternative growth method based on HCl+CO mixture as a TA for more stable relatively fast growth of ZnO single crystals. The thermodynamic analysis for ZnO-HCl-CO/CO2 CVT systems in the closed growth chambers is carried out for wide temperature and loaded TA pressure ranges (Fig. 1). It was shown that HCl+CO gas mixture should provide faster mass transport in comparison with pure HCl, while ZnO-HCl-CO2 CVT system is close to ZnO-HCl case. The influence of HCl/CO composition of the TA mixture, growth temperature in the 925-1050 °C range, density of TA in the 0.5-4 atm pressure range and undercooling in the 30-60 °C range were investigated experimentally on the rate of ZnO mass transport. It was shown that HCl+CO gas mixture provides (i) a higher growth rate, (ii) a tendency of ZnO crystals to have a long prismatic shape (Fig. 2), (iii) a minimization of wall adhesion effect and deformations during a post-growth cooling, and (iv) stable growth of the void-free single crystals with controllable electrical parameters.