of all 30 potato varieties cultivated in colombia only 10 possess a commercial importance. among other factors, this number is limited by the action of endogenous hormones that accelerate different phases of tuberization process, especially in the earliest species. in this work, the samples of tubers from different potato species solanum tuberosum l. vars. ica-unica, tuquerre？a and solanum phureja juz. et buk. var. yema de huevo were collected at the phenological stages of development 03, 10 and 40. later, the concentrations of abscisic acid in the acid fraction and ones of cytokinins in the organic fraction of the extracts were determined by high performance liquid chromatography. the results in studied varieties show a relationship between the early tuberization and aba absence, while the periods of deep latency were related with aba presence; otherwise, the cytokinin levels were high in the varieties with early tuberization. that is to say, it was found in s. phureja juz. et buk. var. yema de huevo, characterized by early tuberization, low aba concentrations and considerable levels of cytokinins, whereas, in varieties with periods of prolonged latency, such as ica-unica and, especially, tuquerre？a, aba concentrations were considerable, but those of cytokinin not.