Microbial hydrolysis of the acetates of unsaturated cyclic terpene alcohols by Pseudomonas sp. NOF-5 isolated from soil was investigated. (±)-trans-Carveyl acetate ((±)-trans-3) was enantioselectively hydrolyzed with NOF-5 strain to give (-)-trans-carveol ((-)-trans-2 of 86.6% optical purity). However, the hydrolysis of (±)-cis-3 was less enantioselective, while (±)-piperitylacetate ((±)-6, a cis and trans mixture) was hydrolyzed to give the (-)-trans- and (-)-cis-piperitols ((-)-trans-5 and (-)-cis-5) in a poor optical yield. In this case, other tert-alcohos, (+)-trans- and (-)-cis-2-p-menthen-1-ols ((±)-trans-7 and (-)-cis-7), were also produced. Furthermore, microbial and enzymic allyl rearrangements of (+)-trans-6 and (-)-trans-verbenylacetate ((-)-trans-11) were studied. Biological treatment of (+)-trans-6 and (-)-trans-11 with NOF-5 or its esterase gave (+)-trans- and (-)-cis-7 and (+)-cis-3-pinen-2-ol ((+)-cis-12), respectively.