Cyclodextrin glucanotransferase [CGTase, E.C.2.4.1.19] is an extracellular enzyme, which catalyzes he formation of ${alpha}$-, ${eta}$-, ${gamma}$- CDs from starch. Their proportions of formations depend on enzyme sources and reaction conditions. To understand what determines the product specificity of CGTases, we examined the alteration of product specificity of CGTase from Bacillus macerans by organic solvent sand pH. At acidic pH range less than pH 6 where the enzyme was unstable, the ratio of ${alpha}$-/ ${eta}$-CD production was increased 4 times more than that at neutral pH range. As we increased the concentration of 2-butanol, ${alpha}$-/ ${eta}$-CD ratio was proportionally increased but / ratio remained constant. The ${alpha}$-/ ${eta}$-CD ratio of products was increased in the reaction media which yielded low products.