A laboratory experiment to measure the collection efficiency of millimeter-sized neutral water drops collecting micron-sized aerosol particles has been conducted. In agreement with the previous studies, the results show that the collection efficiency increases with the decrease in drop size and/or increase in particle size. Further, the collection efficiency is observed to increase with impaction parameter and decrease with the drop Reynold's number. The limited and sparse data obtained in our experiment suggests that the collection efficiency of large drops may attain an upper limit which may be less than unity as the particle diameter approaches 10 μm. Moreover, the maximum collection efficiency attained by such large drops seems to decrease with the increasing drop size. Shape oscillations and the eddy shedding capability of large water drops have been proposed to explain the observed results. ¿ American Geophysical Union 1996