Objectives: Aim of this experimental study was to develop a GC-MS method for quantitative determination of synthetic cannabinoids JWH-018, JWH-019, JWH-073, JWH-210 and ADB-PINACA. Also, our objective was to quantitatively determine these synthetic cannabinoids in urine samples using the developed method. Materials and methods: Standard solutions of synthetic cannabinoids prepared by diluting original standards in methanol were added to the biological sample of urine, that tested negative for substances of abuse, to obtain calibration curves for analyzed synthetic cannabinoids. Using unknown volumes of standard solutions, two urine samples were prepared. The samples were prepared for analysis by liquid-liquid extraction (LLE) and then analyzed by a GC-MS method using mode that simultaneously records total ion chromatogram in the area of 50-600 m/z values and single ion monitoring scanning mode. The temperature program was also optimized. Results: ADB-PINACA, JWH-019 and JWH-210 were confirmed in both analyzed samples, while JWH-073 and JWH-018 were only confirmed in sample 1, to which a larger volume of prepared standard solutions was added. The mass concentrations of detected synthetic cannabinoids were calculated using previously prepared calibration curves. Conclusion: This study confirmed the GC-MS technique for quantitative determination of synthetic cannabinoids in biological samples of urine. In order to increase the stability of the analyzed compounds, it is necessary to include the derivatisation step prior to GC-MS analysis. Due to the increasing presence of new analogues, structurally similar to origin molecules, there is a need for development of analytical methods for the identification of synthetic cannabinoids and their metabolites in biological samples.