Resumo. In Brazil, in order to minimize the impact of native forest exploitation for commercial purposes, forest plantations have been implemented mainly with exotic species. The evaluation of these crops as to the environmental impact on attributes that can guarantee their productivity has received more attention in the last years, and in this context, the study of microbiological attributes. This paper assesses the impact of Pinus sp. (pinus) and Araucaria angustifolia (araucária) forest plantations on the microbiological soil attributes and the structure of bacterial communities, which can act as indicators of soil quality. Soil samples have been collected on three areas of the National Forest of Três Barras, in Santa Catarina (SC) state: one area of native forest (F), one area of reforestation with araucária (A) and one area of reforestation with pinus (P). Later on, the soil was chemically and physically characterized and the microbiological analyses were performed, as basal respiration, β-glucosidase and fosfatase enzymatic activity and analysis of bacterial community structure by PCR-DGGE. Low fertility was presented on all three soils collected, highlighting the importance of microorganisms in order to maintain this environment. The β-glucosidase and fosfatase enzymatic activity were higher on the areas F and A, suggesting a higher presence of important microorganisms for nutrients cycling. The analysis of the bacteria community structure resulted in low distinction between the pinus and the araucária areas. This paper presents that based on the microbiological attributes and structure of bacterial communities of soil, in forest plantations of the Atlantic Forest, it is possible to conclude that araucária is the best alternative for reforestation, aiming the maintenance of soil quality.