The key objective of this study was to measure particle size distributions of paniculate matter emitted from swine buildings. Particle size distribution and concentration emitted from various types of swine buildings were collected and measured. Particle size was measured using four different instruments: a Horiba (Model LA-300, Horiba Instruments, Inc., CA, USA), an Aerosizer DSP (Model 3225, TSI Inc., MN, US4), a Coulter Multisizer (Model Multisizer 3, Beckman Coulter Inc., CA, USA) and a Malvern Mastersizer 2000 (Model Mastersizer 2000, Malvern Instruments Ltd., UK). Dust particles were collected using filters over a 20-hour period. The collected filter samples were analyzed for particle size distribution and particle mass concentration. Mass median diameters and geometric standard deviations were compared with four different particle sizing analyzers. The measured mass median diameter varied from 9 μm to 25 μm, and observed particle mass concentrations ranged from 0.5 to 1.9 mg/m 3. The largest and smallest mass median diameter (MMD) was observed by Horiba and Aerosizer DSP, respectively, in most of the field measurements, and this trend was in accordance with preliminary instrumental examinations conducted in a laboratory. Currently, field campaigns for collection of swine building dust are still in process to cover seasonal variations.