We describe the method of laser induced pyrolysis of gaseous compounds for the continuous production of very fine powders. As an example we report on the chemical reaction of chromyl chloride (CrO 2Cl 2) to chromium (III)oxide which is an active catalyst. It was possible to produce Cr 2O 3 powders of defined and reproducible particle size that could be varied in the range from 50 nm to 350 nm by changing different process parameters such as pressure and nature of the carrier gas, power density of the cw CO 2 laser or contact time between Cr 2O 3 and laser beam. The particles show a narrow size distribution and a regular form, are hardly contaminated, have a large BET surface and are loosely agglomerated. The synthesis of mixed oxides is possible by simultaneous laser pyrolysis of two reactants like chromyl chloride and titanium tetrachloride or vanadyl chloride.