 The aims of this study were 1 to use the FOT to analyze how respiratory mechanics is affected in patients with asbestos exposed, 2 to identify the best FOT parameters for the diagnosis of respiratory changes in these patients 3 Assess whether the presence of obstructive changes is associated with the smoking habit.The control group CG included 24 subjects with normal spirometric data and without a history of smoking or pulmonary disease formed by workers and students UERJ and FioCruz. Volunteers with asbestos exposure were from the Department of CESTEH FioCruz, totaling 24 exposed and 7 with diagnoses of asbestosis. 