In this study, microstructural characteristics and corrosion behavior of UNS S32750 super duplex stainless steel/AISI 316L austenitic stainless steel dissimilar weldments were evaluated. In order to weld the samples gas tungsten arc welding process with direct current electrode negative polarity (GTAW- DCEN) was applied with AWS ER2594 as the filler metal. Since heat input plays an important role in the evolution of austenitic-ferritic microstructures, welding was done at several heat inputs and the effects of heat input on microstructural evolution and corrosion resistance of weld zone were investigated. The effects of post weld heat treatment at 1125°C were also studied. The microstructures were identified using optical microscopy (OM) and scanning electron microscopy (SEM). The corrosion resistance was evaluated through potentiodynamic polarization and cyclic polarization tests in 3.5% NaCl solution at ambient temperature. The results showed that an increase in the heat input in a range of 660-825 J/mm can lead to increase of the weld metal austenite content from 60.79% to 74.47%. A heat affected zone with about 200 micrometers width was created in UNS S32750 super duplex stainless steel base metal due to welding thermal cycles. On the other hand, some delta ferrite was formed in the heat affected zone of AISI 316L base metal. According to the electrochemical tests, UNS S32750 super duplex stainless steel presented excellent corrosion resistance comparing AISI 316L austenitic stainless steel which was attributed to its high chromium and molybdenum content. The UNS S32750 super duplex stainless steel exhibited higher corrosion potential, lower corrosion current density and very higher pitting potential than the AISI 316L austenitic stainless steel. Evaluation of weld metals corrosion behaviors showed that increase of austenite content was lead to reduction of general corrosion resistance, but pitting corrosion resistance was not varied. In general, the UNS S32750 super duplex stainless steel and weld metals exhibited alike pitting potentials (~ 1.0 Vsce). Theoric investigations based on several criteria indicated that galvanic corrosion between AISI 316L austenitic stainless steel and weld metal was significant. Corrosion resistance of UNS S32750 super duplex stainless steel was not severely affected by solution annealing heat treatment (1125 °C / 2hr); however, post weld heat treatment in same condition improved pitting resistance of weld metals. Post weld heat treatment increased pitting potential of weld metal about 25 mVsce. Finally, it should be mentioned that using AWS ER2594 filler metal and heat input control can lead to a weld metal with a better corrosion resistance than the base metals. Since the corrosion resistance of weld metal can not be altered significantly by post weld heat treatment, it is not recommended for this dissimilar joint. Keywords: Super duplex stainless steel, Austenitic stainless steel, Dissimilar welding, Heat treatment, Microstructure, Corrosion behavior.