The application of different mechanical extraction ventilation systems in reducing and controlling dust concentrations in weaned and finishing pig houses was analyzed and discussed in this work. Dust concentrations and airflow velocities have been measured at 20 measuring points, smoothly positioned over the house cross section, in the net consisting of 4 horizontal and 5 vertical rows. The lowest horizontal row was positioned at the pigs breathing zone (40 cm above the floor), and the highest (fourth) horizontal row was positioned at the workers breathing zone (160 cm).