In this study, we aimed to develop a headspace gas chromatography-mass spectrometry method for determining the total cyanide concentration in the forensic evidences. Total cyanide content of the samples was calculated based on the hydrogen cyanide gas concentration evaporated from the liquid sample in the headspace vial. Hexacyanoferrate(II) was used for the optimization of headspace oven temperature. We determined that iron-cyanide bonds were completely degraded after 0.2 mL of the sample was treated with 1 mL of 1 M sulfuric acid under the optimized headspace conditions where the temperature and the heating time were 120 °C and 12.5 min, respectively. Satisfactory recovery results for both aqueous and blood samples were obtained. The method was linear in the range 0.05 – 10 µg ‾1 of cyanide which was a suitable range for toxicological investigations. The proposed method was validated and applied to the postmortem blood samples, drinking waters, and the other forensic evidences. The proposed method can easily be performed not only in the forensic laboratories, but in the related laboratories where the total cyanide analysis is a critical issue.