Resumo. This study was designed to determine the criteria and the parameters needed for the inventory and the classification of the secondary forest in the Atlantic coast of Santa Catarina state, in Brazil. The forest inventories were conducted in 160 plots at four different stages of natural succession, in all forest of the state. It is proposed that inventories needed for the legal classification of secondary forests should include all individuals of each plot ≥5cm DBH and that basal area should be the central variable used to assign these forest formations in successional stages. This study also suggests the need to review the current regulation parameters in this place for the forest classification of Mata Atlântica defined by the current resolution.