Integrated interpretation errors mainly depend on the type of applied algorithm. The ways for calculation of the reliability of single geophysical method and the reliability of information obtained by a set of geophysical methods is shown. The methodology of some information parameters calculation is shown in detail. Integrated interpretation can be deterministic, probabilistic and mixed (probabilistic–deterministic). A notion of Physical-Geological Model necessary for combined geophysical analysis is explained. Several examples illustrate effective integration of thermal and other geophysical methods.