The selective hydrogenation of (-)-alpha-pinene in the liquid phase over several supported and skeletal nickel catalysts prepared by electroless deposition was studied. The (-)-alpha-pinene, which had bridged bicyclic structure, was chemisorbed on the catalysts with minimum steric hindrance, and the hydrogens were transferred to the proximal face of the double bond to yield the main product. The results showed that the selectivity of cis-pinane increased with decreasing acidity of support, temperature of hydrogenation, and electron density of nickel. On the other hand, the selectivity of cis-pinane increased with the pressure of hydrogen. A reaction mechanism with isomerization as well as half-hydrogenation was proposed. On the basis of both the steric and electronic effects, three types of reaction conditions were included. Steric effect favors the direct hydrogenation, which results in cis addition. Electronic effect, however, induces indirect hydrogenation, which produces more stable trans-pinanes. In the hydrogenation of(-)-alpha-pinene, which was a nucleophilic reagent, the role of boron and phosphorus in nickel catalysts was described as an electron donor and acceptor, respectively. The experimental results correlated well with the theoretical analysis.