The ketonization of propyl propionate over a catalyst of zinc chromite type at 300-400˚C in the presence of water vapour has been investigated. It was found that the maximum degree of ketonization (89.7 mol%) was achieved at 350˚C temperature while the propyl propionate conversion was 99.7%. As by-products of the reaction, methyl ethyl ketone, propanol, propanal and propionic acid were detected. The composition of gaseous reaction products was also studied; hydrogen and carbon dioxide were found to be the main components. The content of CO, CH4, C2H6 and C3H6 significantly rises at 375-400˚C, when the importance of molecule destruction increases. Degrees of ketonization of the corresponding ester, carboxylic acid, aldehyde, alcohol and ethyl acetate are compared. It is found that the ketonization of propyl propionate proceeds more selectively than in the cases of corresponding alcohol and aldehyde and, in this respect, only slightly falls behind ketonization of acid. It is concluded that ketonization of esters over chromite type catalysts is a perspective method for producing ketones. Selectivity of propyl propionate ketonization is about 2% lower than the selectivity of ethyl acetate, and the optimum is reached within narrower temperature range.