Endogenous carbohydrate (fructose, glucose and sucrose) fractions were measured in calli of potato genotypes with different field tolerance to drought. Under in vitro stress conditions induced by 0.8 M mannitol, sucrose level of calli increased extremely in medium-tolerant (by 424.5%) and sensitive (by 302.7%) genotypes whilst the rate of increase was 12-18-times lower in the drought tolerant variety. Results suggest the applicability of sucrose as biochemical marker for distinguish drought tolerant genotypes from great population in callus culture.