A brief survey of the major techniques of raindrop size-sampling is given. The filter-paper technique, finally adopted for use in this study, adapts itself admirably to the sampling of Hawaiian orographic rains. The change in the drop-size distribution of rain as it falls from cloud to ground may be considerable. It is affected by wind shear, gravity separation, evaporation and drop collision. The evaporation error alone can be appreciable. The many small drops of the Hawaiian orographic rains may completely evaporate in a sub-cloud fall of only 1000 m. The evaporation problem was eliminated, and the others minimized, by sampling all the orographic rain at cloud base or within the cloud itself. Drop-size distributions were obtained in such non-orographic rains as thunderstorms and cyclonic storms. The pertinent meteorological parameters, such as liquid-water content, median drop diameter, and radar reflectivity, agree reasonably well with the values given by other investigators. The measurements ... Abstract A brief survey of the major techniques of raindrop size-sampling is given. The filter-paper technique, finally adopted for use in this study, adapts itself admirably to the sampling of Hawaiian orographic rains. The change in the drop-size distribution of rain as it falls from cloud to ground may be considerable. It is affected by wind shear, gravity separation, evaporation and drop collision. The evaporation error alone can be appreciable. The many small drops of the Hawaiian orographic rains may completely evaporate in a sub-cloud fall of only 1000 m. The evaporation problem was eliminated, and the others minimized, by sampling all the orographic rain at cloud base or within the cloud itself. Drop-size distributions were obtained in such non-orographic rains as thunderstorms and cyclonic storms. The pertinent meteorological parameters, such as liquid-water content, median drop diameter, and radar reflectivity, agree reasonably well with the values given by other investigators. The measurements ...