A characterization of the air in underground coal mines is important, therefore, it is possible that it is focused on the safety of the work and the environment. (CH4) and Carbon Dioxide (CO2) along the ventilation system of three coal mines, named (A, B and C), all located in the South Catarinense deposit, Paraná Basin, Bonito Formation, the Barro Branco layer (mines A and C) and Bonito layer (mine B) and also, make estimates of the emission of greenhouse gases (CH4 and CO2). From collection that the first campaign as samples were collected with bags in mines A and B, other campaigns such as collections Were carried out with borosilicate collecting flasks. Surveillance, temperature, pressure and humidity measurements were also carried out at different points of the mines for a higher flow rate determination. Gas analyzes were performed by gas chromatography. The results indicated as higher concentrations of CH4 are present in Mine A, but all concentrations are below the explosive limit of this gas (50,000 ppm). CO2, despite having similar concentrations in the three mines, also stands out at mine A, presenting higher concentrations in emanation areas determined for NR15 (3,900 ppm) and MSHA (5,000 ppm). As emission estimates of CH4 and CO2 (GHG) were carried out with different methodologies in which they differ according to the values of emission, concentration, coal production and total ventilation flow. Taking into account that the results obtained in Brazil refer to the emission of CH4 in underground coal mines, in which, considering the mining characteristics, it is estimated that the values found in the literature overestimate the values emitted by each mine. It should be noted that the results obtained in this study are an attempt to improve the emission calculations. However, to improve the accuracy of inventories, more sampling should be done covering all mines in operation in the country.