Tortuosity tau is physically defined as the ratio (or the square of the ratio) of the effective length of pore channels (through which the hydraulic flow and electric current are conducted) to the length parallel to the overall direction of the pore channels in a porous medium. It has a significant influence on hydraulic flow and electric current because of its response to the variations in lithology, pressure and petrophysical properties. Determination of tortuosity enables one to understand the mechanisms of hydraulic flow and electric current and the channel-network complexities in porous media. In this study, physical and mathematical aspects of tortuosity ale discussed. Also, tortuosity is mathematically derived as the square root of the dimensionless formation resistivity factor limes fractional porosity. Tortuosity can be successfully used for interpretation of the physical behavior of unconsolidated and consolidated porous media, similarly, and for formations characterized by high degrees of compaction, heterogeneity and anisotropy, as in the case of the Hibernia and Terra Noun reservoirs, off the eastern coast of Canada.