Silicon nitride (Si3N4) has been obtained from the carbothermal reduction of rice husks by applying the constant-rate-thermal-analysis (CRTA) method. Under this method, the reaction rate of carbothermal reduction can be controlled and at the same time the CO concentration generated is maintained constant at a previously selected value by the user. By using this synthesis technique it has been possible to obtain ceramic powder from rice husks with a determined phase composition and a controlled microstructure. Therefore, rice husks have great potential as a raw material for producing Si3N4 by the CRTA method.