GaN based blue light emitting diodes were characterized, using deep level transient spectroscopy technique. Nine defects having ionization energies: 0.06, 0.08, 0.09, 0.14, 0.10 , 0.14, 0.14, 0.16 and 0.65 eV and corresponding capture cross-sections (σ∞ )4.0 × 10−14 , 1.3 × 10−13 , 7.6 × 10−14 , 6.95 × 10−13 , 3.53 × 10−14 , 1.6 × 10−13 , 8.0 × 10−14 , 7.34 × 10−14 and 1.8 × 10−5 cm2 were identified. Respective concentrations were found to be 8.81 × 1013 , 8.56 × 1013 , 8.90 × 1013 , 8.68 × 1013 , 8.62 × 1013 , 8.56 × 1013 , 8.66 × 1013 , 8.57 × 1013 , 8.54 × 1013 , 8.68 × 1014 , and 8.46 × 1014 cm−3 .