A new model has been developed for the prediction and correlation of mass-transfer rates in distillation columns containing random packings. Emphasis is placed on the characteristics of the newer "high-efficiency" random packings : IMTP, CMR, Fleximax, and Nutter. These packings are of the high void fraction, through-flow type and have become quite popular for new designs as well as for retrofits. In building the model use has been made of a large bank of experimental data from the laboratories of Fractionation Research, Inc., and the Separations Research Program (SRP) at The University of Texas at Austin. The model is based on an earlier SRP study of liquid holdup and gas pressure drop in beds of random or structured packing (Stichlmair et al. Gas Sep. Purif. 1989, 3, 19]. The only packing parameter needed is a "packing characteristic" which has a value of about 0.030 for a 2-in. Pall and Raschig rings and about 0.050 for the 2-in. nominal size of the high-efficiency packings listed above. The model was found to fit 95% of 326 experimental values of height equivalent to a theoretical plate (HETP) to within +/-25% and all values within +/-30%.