To assess the iron overload in human tissue especially in the heart of transfusion-dependent thalassemia patients using cardiac magnetic resonance imaging (CMRI) technique has been widely used to evaluate cardiac iron deposition because of its non-invasive procedure. The iron measure from this technique is represent as T2* (T2 Star) value. Cardiac T2* software was developed. The software was measuring T2* value from DICOM image with two algorithm processing components; regions of interest (ROI) identification, and T2* optimization. The software preliminary testing was performed using test cases DICOM image, three times repeating, from both healthy volunteer and thalassemia patient with cardiac iron overload, then compared T2* value with the reference tool (CMRtools with ThalassemiaTools plug-in). Mean T2* value analyzed from healthy volunteer CMRI was 22.36 (±0.94) and 37.10 (±1.62), respectively. While the mean T2* value analyzed from thalassemia patients CMRI was 15.52 (±0.85) and 18.67 (±1.15) in reference software and CMUT2Star software respectively. In conclusion, CMUT2Star produced a higher T2* value than the reference tool. Software has no any errors and no conflict with testing platform. The algorithm in T2* optimization component need to be adjusted in order to produce the accuracy and robust T2* value.