The flow of a polypropylene in a self-wiping corotating twin-screw extruder was characterized by measuring the pressure, temperature, and residence time along the screw profile. The influence od the operating conditions (feed rate, screw speed, barrel temperature) and screw profile was studied. Flow modeling was performed using the Ludovic(R) software and measured and calculated pressure, temperature, residence time,and energy consumption were compared. The values of the temperature close to the melting zone were overestimated by the model, which considers instantaneous melting upon the first restrictive screw element. If the program assumes that melting occurs at the screw location identified experimentally, a correct description of the temperatures along the screw profile is produced. The influence of the processing conditions (feed rate, screw speed, barrel temperature, screw profile) is well described by the model. These results put in evidence the importance of including an adequate melting model in the modeling of the twin-screw extrusion process.