This paper summarizes available methods for interpreting flow tests in fissured formations. The methods are taken from the geotechnical, ground-water, and petroleum literature. These are usually based on “equivalent reservoir” solutions, which attempt to relate the actual fissured reservoir behavior to that of a known theoretical model, homogeneous or heterogeneous, of lower complexity. The double-porosity concept, used by many authors for ground-water and petroleum engineering problems, is critically reviewed and the relationship between the various available solutions is established. The methods presented in the paper are illustrated with well-test data from aquifers and oil reservoirs of various characteristics.