In this paper, we present the results of a series of wind tunnel tests of the airflow through a shrouded probe designed by Ram ct al. (1995, J. Aerosol. Sci. 26, 945-962) for high velocity airborne sampling of insoluble aerosol particles in the size range 0.1-15 mu m diameter. Tests included flow visualization using a laser light-sheet and hot wire anemometry measurements of air velocity profiles within the shroud upstream of the sampling probe with the probe operating at angles of attack from 0 to 15 degrees. We discuss the effectiveness of the shroud in making the flow into the probe isoaxial for situations where the sampler is at small angles of attack and comment on the role of the shroud as an effective flow decelerator. We conclude by comparing the wind tunnel measurements with numerical simulation studies of the airflow through the sampler at 0 degrees angle of attack.