ABSTRACT: The article describes main physical principles valid for multiphase systems in porous rock medium with application into light non-aqueous phase liquids (LNAPL) forms of occurrence and LNAPL migration, as is described in chosen literature. Resulting impact of these physical principles determines the behavior of LNAPL in porous rock media and monitoring or remediation wells, where phenomena take place such as: the relative phase permeability, or the total immobility of a particular phase in the porous media, the apparent thickness of LNAPL in the well, residual saturation and complex regime of LNAPL. These phenomena are manifested in varying intensity, which is affected by the lithological characteristics of the environment – in particular the size of the pore spaces and their interconnections, as well as the relative amount of the particular phase – the degree of saturation of the environment by the phase and history of particular site. Thorough understanding of LNAPL behavior is essential prerequisite for design of effective remediation system and proper remediation works procedure.