Metal organic frameworks (MOFs) are promising nanoporous materials in gas separation applications due to their tunable pore sizes, large surface areas, high porosities, good thermal and mechanical stabilities. In this study, large-scale computational screening of 278 different MOFs was performed for separation of C2H6/C2H4 and C2H6/CH4 mixtures using molecular simulations. This is the largest number of MOFs screened in the literature for these two gas separations. We first compared simulated gas adsorption data with the experimental measurements to validate the accuracy of our computational approach. Molecular simulations were then used to estimate adsorption selectivity, working capacity and sorbent selection parameter of MOFs for C2H6/C2H4 and C2H6/CH4 separations. Results showed that there is a significant number of MOFs predicted to exhibit significantly higher adsorption selectivities and working capacities compared to zeolites. Membrane selectivities of MOFs that show the highest adsorption selectivities were also calculated and compared with selectivities and gas permeabilities of zeolite and polymer membranes. Results show that MOFs can be strong alternatives to traditional membranes for C2H6/C2H4 separations. (C) 2015 Elsevier Ltd. All rights reserved.