The particle size distribution of the shielded metal arc welding fumes is studied. The laser aerosol spectrometer and optoelectronic aerosol counter with the total measurement range of 0.15-10 mu m were used. It is demonstrated that the number-based size distribution is described by the three-modal lognormal distribution, where the first two modes are the result of the liquid-phase and solid-phase coagulation and the third mode is the coarse fume particles. The linear dependency of the average size of the particles on the product of welding parameters: the arc resistance, the wire feed rate and the electrode sectional area is revealed. (C) 2013 Elsevier Ltd. All rights reserved.