We describe the application of a nephelometer to in‐situ, real‐time measurement of the integrated backscattering coefficient σbs of cloud drops. For thin and moderately thick clouds, this quantity is related to the cloud albedo A, for 0° zenith solar radiation, through the relation A=σbsL, where L is the geometric cloud thickness. The instrument was used in a field experiment on El Yunque peak in Puerto Rico. The measured σbs values are in agreement with results of Mie theory calculations, using independently measured cloud drop concentration and size distribution.