The morphological variability in human lungs was simulated by 10 multiple-path lung models, generated on the basis of probability distributions and correlations of airway parameters provided by the stochastic lung model of Koblinger and Hofmann (Phys. Med. Biol. 30 (1985) 541). Total, regional and generation-per-generation deposition was computed for particle sizes in the range of 0.01-10 mum under resting breathing conditions. Our calculations suggest that structural and volumetric differences of lung morphologies among different individuals are primarily responsible for the experimentally observed intersubject variability in total and regional deposition under controlled breathing conditions. Individual differences in deposition among single airways can be substantially larger than those in total and regional deposition. Furthermore, variations are most pronounced for small (0.01 mum) and large (10 mum) particles.