Hydrodistillated essential oils of Ziziphora clinopodioides ssp. rigida from nine populations of the Lashgardar protected region (Hamedan Province, Iran) were analyzed by using GC and GC/MS techniques to determine the intraspecific chemical variability. Altogether, 39 compounds were identified in the oils, and a relatively high variation in their contents was found. The main constituents of the essential oils were pulegone (0.7-44.5%), 1,8-cineole (2.1-26.0%), neomenthol (2.5-22.5%), 4-terpineol (0.0-9.9%), 1-terpineol (0.0-13.2%), neomenthyl acetate (0.0-7.1%), and piperitenone (0.0-5.4%). For the determination of the chemotypes and the intraspecific chemical variability, the essential oil components were subjected to cluster analysis (CA). The five different chemotypes characterized were Chemotype I (pulegone/neomenthol), Chemotype II (pulegone), Chemotype III (pulegone/1,8-cineole), Chemotype IV (neomenthol), and Chemotype V (1,8-cineole/4-terpineol).