The hydro-distillation of the aerial part of Capparis spinosa gives transparent oil with a low yield (0.01%). The essential oil analysis of fifteen populations was carried out using GC-GC/MS. 89 components were identified representing an average of 92.63% of the total oil. The chemical composition of this species are dominated by n-nonanal with an average of 14.89 ± 7.59, palmitic acid (11.88 ± 5.28), isopulegyl acetate (4.29 ± 4.41), heneicosane (3.32 ± 5.49) and α-pinene (2.42 ± 3.96). This study allowed us to identify within the populations several chemotypes; the chemotype to α-pinene–henecosane characterizes the populations of Tizi n’bechar and Kherrata. The chemotype to α-pinene-β-phellandrene characterizes the population of Beni Aziz. The chemotype to n-nonanal-β-anisyl alcohol characterizes the populations of Amoucha and Mansoura, while the chemotype n-nonanal-hexadecanoic acid characterizes the rest of the populations (Aftis, Allaghen, Alloune, Beni Fouad, Bibans, Bordj Zemoura, Colla, Hasnaoua, Theniet Ennasr and Tunisia) with several sub chemotypes.