Some issues related to development of a three-dimensional simulation of magnetron devices are discussed in this paper. The processes are studied in the whole of the cylindrical space with variations of the electric and magnetic fields taken into account. In addition, the split anode structure and possibility of several modes to occur and to mutually compete are taken into account. The large particles approach is used and all main equations including the equations of motion, Poisson, interaction, etc. are solved numerically. The suggested models were instrumental in development of a program intended for analysis of physical phenomena and calculation of M-type oscillators and amplifiers (platinotrons, surface wave magnetron (SWM) amplifiers) with a drift zone, etc. Computer simulation of magnetron oscillators was performed and the results are presented. Practical application of the software developed both for magnetron devices design and analysis of different physical phenomena is discussed in detail. (C) 2003 Published by Elsevier Science B.V.