The use of seed tubers of suitable bud stage is of paramount importance in potato crop production because it enables obtaining the number of stems closest to that desired. The objective of this study was to study the influence of bud stage and seed potato tubercle size on the plant characteristics of the potato var. Agata. The experiment was carried out between January and April 2017. The treatments included two sizes of seed tubers of Agata variety types I (50-60 mm) and III (30-40 mm) and four stages of growth (A, larger sprout, shoots bigger than 1 cm; B, shoots of approximately 0.7 cm; C, shoots of approximately 0.4 cm; and D, less budding, incipient shoots of up to 0.1 cm). The number of stems and tubers per plant, the number of tubers per stem, the production and classification of tubers, and the average mass of tubers were evaluated. A positive association was found between the seed tuber size and sprouting stage and the number of stems per plant. The number of tubers and stems per plant was positively related to the mass of the seed tuber, especially when the tuber was most sprouted. The use of type I seed tubers with an earlier budding phase favors the production of the highest number of tubers per plant. Minor seed tuber yields a lower number of tubers per plant but yields a higher average mass of tubers. The use of smaller seed tubers (type III) is recommended because they could present a higher productive potential and a higher percentage of large tubers.