To improve fertilizer use efficiency and minimize its negative impact on environment, controlled release fertilizer (CRF) systems were prepared. A series of biodegradable gelatin hydrogels was synthesized by using glutaraldehyde (GA) as crosslinker for controlled release of ammonium nitrate (AN) and monoammoni urn phosphate (MAP) fertilizers. Characteristics of the hydrogels were investigated by swelling and degradation experiments and SEM analysis. Increasing amount of GA/gelatin ratio caused the decrease in S% values from 332 to 218. Release of AN and MAP from gelatin hydrogels versus time was followed, and it is found that the release gently increased at first and then complied between 40-50 h. Zero order release kinetic was mention for the gelatin hydrogels/fertilizer systems prepared in this study.