A numerical approach has been used to evaluate the effect of joint geometry parameters on the permeability of jointed rock. The equivalent continuum approximation for jointed rock masses was found to be strongly dependent on the relative orientation of joint sets for joint sets having the same length and density distributions. This dependency on relative orientation was found to be more pronounced with decreasing density and size. Chance for equivalent continuum behavior was found to increase as the angle between joint sets approaches 90 degrees for the case of rock blocks having only two joint sets. A strong correlation was found between the directional coefficient of permeability and the fracture tensor component for the connected joint elements calculated in a direction perpendicular to the direction of permeability. Rock Mechanics Daemen & Schultz (eds).