The sugar content in the potato tuber determines the optimum harvest time, the type of processing and its handling during storage. The aim of this study was to evaluate the growth and yield of four potato varieties under greenhouse conditions and to determine the soluble sugar content of this tuber at different maturity stages. For this, potatoes (5 ± 1 g) of four varieties were sampled at four maturity stages, from the beginning of tuberization to physiological maturity, in which the soluble sugar content was determined by high-performance liquid chromatography (HPLC). The Alpha variety had the longest growth cycle (1,230 degree days, P ≤ 0.05), while Mondial had the highest yield (380 g, P ≤ 0.05), 75, 31 and 31 % more than Vivaldi, Alpha and Atlantic, respectively, attributed to the highest average tuber weight (61 g, P ≤ 0.05). The highest content of sucrose, glucose and fructose (7.65, 2.22 and 0.37 mg·g-1, respectively) was recorded 21 days after the start of tuberization, quantities that decreased (P ≤ 0.05) during tuber development. Atlantic stands out with the lowest levels (P ≤ 0.05) of sucrose, glucose, fructose and total sugars in the different stages of tuber maturity. Average tuber weight was negatively correlated (P ≤ 0.05) with the contents of sucrose, reducing sugars (glucose and fructose) and total sugars.