The synthesis of pure bismuth molybdates (alpha, beta and gamma phases) using a novel method - spray drying - has been studied and successfully applied. It is shown that it is possible to control the synthesis of mixtures of different bismuth molybdates using spray drying. The influence of the relative molar ratio of bismuth to molybdenum constituents on the formation of different bismuth molybdate phases has been investigated. Starting from spray-dried precursors, thermal details of the phase diagram of the Bi2O3-MoO3 system can be accurately reproduced and very pure phases can be easily obtained. Spray-drying is compared to conventional precipitation and solid-state reaction and the obtained products were characterized by XRD, IR, Raman, SEM, BET and DTA.