An experiment was conducted to assess the spatial variability of dust within the airspace of an occupied piggery. Measurements of airborne and settled dust were made for 16 d at 16 locations within a 180 place, partially slatted-floor, grower-finisher piggery. Eight locations were in a vertical cross-section covering half the width of the building. Two of these locations were used in conjunction with 8 further locations over the remaining pen barriers to establish a horizontal sampling plane. Aerial dust samples were collected every 24 h and settled dust samples every 4 days. Particle size analysis was carried out on all of the settled dust and half of the aerial dust samples. Measurements were made of airspace temp. and air velocity at each sampling location, and of pen cleanliness throughout the building. Results are discussed.