This contribution is intended to introduce the hybrid model MODFLOW-2005 Conduit Flow Processes (CFP), which is able to compute groundwater flow processes within karst aquifers. The approach couples a continuum representing the low conductive matrix with a discrete pipe network. First, some simple examples are presented to validate the operation of the CFP model. Next, the functionality of the software is demonstrated for a synthetic karst aquifer. Advantages as well as restrictions of MODFLOW-2005 CFP are discussed to support potential users. Since April 2008, MODFLOW-2005 CFP has been available free of charge from the United States Geological Survey (USGS) website.