The stratospheric aerosol particle size distribution has been measured at 34¿S for the period 1974--1979. Results from two measuring techniques-in situ single-particle counting and jet impaction-agree well. The size distribution is shown to be described equally well by either a log-normal or zero-order logarithmic function. Observed distributions below 22 km agree substantially with model predictions for r>0.1 μm indicate fewer particles at smaller radii.