Catalytic transformation of cyclohexanone by nitric oxide and ammonia to cyclohexanone oxime, its rearrangement to caprolactam, and its polymerization to polycaprolactam has been studied in the liquid phase over solid catalysts, The influence of various catalysts and process parameters on the oximation reaction is reported. A maximum yield of 37.78% with a selectivity of 80.95% for caprolactam could be achieved, over a synthetically prepared Al2O3-SiO2 catalyst, at a cyclohexanone : NO : NH3 molar ratio of 1 : 2.9 : 1.7 and a temperature of 348 K. In this process the production of oxime and its rearrangement to caprolactam occur simultaneously. The resulting caprolactam polymerises later to give a molecular weight ranging from 500 to 5000. A tentative mechanism for the reactions is suggested.