Experimental data are reported on total deposition of a solid monodisperse aerosol along the human respiratory tract in a study wtih 25 healthy adults of both sexes. The test aerosol was generated by condensation of carnauba wax vapor onto suitable condensation nuclei. The particles were solid spheres at body temperature and ranged from 0.2 to 2 µm diameter, with a geometric standard deviation of less than 1.1. The deposition efficiency was assessed by photometric measurement of light scattering at 90° in the inhaled and the exhaled air. On each exposure subject the relevant spiro-metric parameters were assessed in order to correlate these with the deposition data. Measurements were made at constant respiratory frequency and tidal volume, and at spontaneous respiration conditions.