This study explores how gamma radiation affects DNA concentration and the stability of autosomal short tandem repeat (STR) markers in buccal swab samples. A total of 160 swabs from 20 volunteers were exposed to therapeutic radiation doses ranging from 1 to 80 Gy. The results revealed a clear dose-dependent decrease in DNA concentration, indicating significant DNA damage as radiation increased. Despite this, the autosomal STR markers remained stable across all doses, demonstrating their robustness against radiation-induced damage. These findings are crucial for clinical and forensic applications, confirming that STR profiling remains reliable for cancer patients undergoing radiation therapy and in forensic cases involving irradiated DNA. The study emphasizes the value of STR markers in genetic analysis under challenging conditions and highlights the need for further research on their long-term stability in diverse biological contexts.