In this study, performances of Ranque-Hilsch Vortex Tubes (RHVTs) were modeled under three different situations based on inlet pressure and the ratio of mass flow rate of the cold stream to the mass flow rate of the inlet stream (ξ) by fuzzy logic approach. 1st situation is the conventional RHVT. 2nd situation is the threefold cascade type RHVT. Here three RHVTs were used. 3rd situation deals with the six cascade type RHVT. In this case, six RHVTs were used. Input-output parameters were described by Rule Based Mamdani Type Fuzzy (RBMTF) with if-then rules. The performance parameters are the difference between the hot and cold stream temperatures (∆T), the cold flow fraction (ξ), inlet pressure conditions. The comparison between experimental data and RBMTF is done by using statistical methods like absolute fraction of variance (R2). The actual values and RBMTF results indicated that RBMTF can be successfully used for the analysis of performance RHVTs.