With increasing demand for steels for drawing at higher speeds, the quality, in terms of internal defects and macro structural features (central porosity, equiaxed zone, etc.), of billets has become of paramount importance. By optimizing the Electro Magnetic Stirrer (EMS) parameters viz., EMS current and frequency the severity of defects, area of columnar zone as well as central porosity, in continuously cast billet can be effectively minimized. The result would be an increase in equiaxed zone area and improved internal soundness. In the present work attempts have been made to determine the best combination of EMS current as well as frequency to ensure good internal soundness of billets. The EMS current and frequency were changed to different values in the range of 300A to 350 A and 4Hz to 6Hz respectively. Corresponding billet samples were collected for macro structural evaluation. The samples were scanned using an immersion ultrasonic C-scanner to get images of samples. Macro structural features revealed by ultrasonic C-Scan were analysed for determining the best combination of EMS parameters. It was observed that in the range under trial, % equiaxed zone and % central void area were not affected significantly by varying the EMS parameters.