Andean tubers are an important source of starch. Although potatoes, sweet potatoes and cassava are the best-known sources, there are other underutilised tubers such as oca, arracacha or mashua, which are mainly consumed by the rural populations surrounding their production area. However, they are not typically used for large-scale applications, giving them a greater added value. The aim of this study was to evaluate the potential use of oca (Oxalis tuberosa) starch to obtain ethanol, studying the optimal conditions of starch enzymatic hydrolysis and subsequent alcoholic fermentation. An initial screening using a Plackett/Burman design (15 treatments, performed in triplicate) to identify the independent variables with the highest impact on the hydrolytic process was applied. Subsequently, the identified variables were used in a Rotational Central Composite Design (CRDC) (11 treatments, performed in triplicate) to determine the optimal values of these variables in the hydrolytic process. Among the main results, the concentration of the enzymes had a significant impact on the hydrolytic process, achieving a conversion of up to 93% in starch hydrolysis to dextrins (liquefaction) at an optimal α-amylase concentration of 0.41%, as well as the subsequent hydrolysis of those dextrins into fermentable sugars (saccharification) at rates greater than 93% at an optimal glucoamylase concentration of 0.75%. In the alcoholic fermentation stage, a conversion efficiency of sugars into ethanol of 89% was obtained using yeast extract as the N source for the yeast Saccharomyces cerevisiae. Based on the results, for every 1000 kg of oca, up to 30 L of ethanol can be produced, which can later be used for different purposes such as the production of alcoholic beverages, biofuel, as well as for medicinal use, among other applications. These results, despite being obtained at the laboratory level, may have practical implications for optimizing hydrolysis processes and guiding future research to obtain ethanol from other underutilized sources of starch.