The epoxidation of 1-octene with t-butyl hydroperoxide in the presence of Mo(CO)(6) has been studied. The influence of the crucial parameters on the yield of 1,2-epoxyoctane in relation to hydroperoxide, on the hydroperoxide conversion, on the selectivity of the transformation of 1-octene to epoxy compound and on the yield of 1,2-epoxyoctane in relation to 1-octene has been described by the use of regression functions in the form of a second order polynomial. The optimal values of parameters: reaction time, temperature, olefin to hydroperoxide mol ratio, Mo(CO)(6) to hydroperoxide mol ratio, ensuring the maximum values of these functions have been determined.