Drop size distributions have been measured in a 39 mm annular centrifugal extractor using phase Doppler particle analyzer (PDPA). The power consumption and the interfacial tension have been varied in the range of 10-450 kW/m(3) and 13-33 mN/m, respectively. The two liquid phases have been selected with different density and viscosity ratios. The results have been analyzed using Rosin-Rammler distribution function. A correlation has been developed for the drop size distribution. The same has been compared with the correlations in the literature. (C) 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.