Kinetics of the liquid-phase isomerization of enantioisomers of alpha-pinene using natural clinoptilolite was investigated. The experimental ranges of temperature and pressure (N-2) Were T= 120-160 degrees C and P = 1-10 bars, respectively. Initially, mainly camphene and limonene were produced; the ratio of enantiomers corresponded to the ratio of +/- isomers in alpha-pinene. At relatively high conversions other monocyclic (terpinene and terpinolene) and tricyclic products (tricyclene) were formed. A kinetic model is developed which described the experimental data well.