Within SMEs, medium-sized farms correspond to a farm production unit where management and decision-making on the farm is concentrated on one person; there is an important gap in the access and information management, which translates in management problems. The objective of this work is to determine management failures as an input for a public policy of business development for the medium farms of the Central South of Chile. This study is exploratory, due to the limited information disaggregated on the level of business management in medium-sized farms. As a measuring instrument, a checklist was applied between the 2013-2014 to 2016-2017 seasons, based on Chilean Standard 2909 (NCh 2909), to 35 medium-sized farms located in the O'Higgins Region. Among the main results, a positive medium correlation is between the management levels obtained with the farm size; the more important management failures are within strategic area, represented by a low presence of a management system, of a strategic plan and of a procedure for reviewing information for decision-making. In conclusion, the diagnosed management level presents significant global failures in a strategic field that may affect its business development, being the degree of progress in management correlated with the farm size, which provides relevant inputs to elaborate a public policy aimed at strengthening business management in agricultural production units.