A simple capillary gas chromatography method using a flame ionization detector has been developed and validated for the quantitative determination of trace analysis of 2, 2’-Azobis-Iso-Butyro-Nitrile (AIBN) and Ditertiary Butyl dicarbonate (DIBOC) in Lenalidomide [LEN] drug substance. Efficient chromatographic separation was achieved on SPB-1, 30 m long with 0.53 mm; 1.0 µm film thickness consists with 100% Dimethylpolysiloxane as stationary phase. The run time was 25 min, employing programmed temperature with split mode (1:5). The analytical method validation is essential for analytical method development and tested extensively for Specificity, Linearity, Precision (repeatability and reproducibility), Accuracy, Robustness, Range, Limit of Quantization (LOQ) and Limit of Detection (LOD). The achieved Limit of Detection (LOD) values were 3.7, 4.0 µg/g, limit of quantization (LOQ) values were 11.2, 12.0 µg/g for AIBN and DIBOC respectively. The method was found to be linear in the range between 3.7 µg/g and 2250 µg/g with correlation coefficient 0.9999 and 0.9999 for AIBN and DIBOC respectively. The average recovery range obtained for these two impurities was between 100.0% and 101.4%. The developed method was found to be linear, robust and rugged for the determination of AIBN and DIBOC in LEN drug substance. The obtained experimental results are discussed in this present article.