In this study, biotransformation of menthol by sporulated surface culture of Aspergillus niger and Penicillium sp. was studied. The main bioconversion product obtained from menthol of A. niger was cis-p-menthan-7-ol and the main products obtained by surface Penicillium sp. were limonene, p-cymene and gamma-terpinene using sporulated surface culture. The pathways involved in the biotransformation of menthol by A. niger and Penicillium sp. to main products are also discussed.