Measurements of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate matters near the traffic road with different particle sizes were carried out by using a low- pressure cascade impactor from 17 Jan. 2005 to 04 Feb. 2005 in Ho Chi Minh City, Viet Nam. Average temperature during the sampling periods was 26°C (ranged from 19 to 34°C). PAHs were analyzed by high performance liquid chromatography with fluorescence detection. Total PAHs contents were mainly concentrated in particles with aerodynamic diameter smaller than 0.4μm. The particle size distributions of particulate matters (PM) and PAHs were bi-modal with a peak in fine particle mode (‹2.1μm) and another peak in coarse particle mode (›2.1μm). PM occupied approximately 80% in the coarse particles, conversely, about 80% of PAHs content associated with airborne particles was found in the fine particles smaller than 2.1μm.