Hydrogel has a wide range of applications, especially in health and medical applications for antibacterial material. Studies that lead to the development of antibacterial hydrogel have been reformed, one of which is the study of the synthesis of hydrogels from CMC and Ag using in situ reduction method. In general to obtain antibacterial properties on the hydrogel, the addition of reagents that has antibacterial properties is needed. In this research, the synthesized antibacterial hydrogel used natural biocompatible polymer as base material to obtain biodegradable and biocompatible properties. Silver nitrate added to the hydrogel are reduced to nanoparticle size and the concentration were varied (500 ppm, 1000 ppm and 1500 ppm) in order to produce antibacterial and super absorbent composite material. Based on the results, the highest swelling ratio was obtained when the antibacterial reagent concentration is 500 ppm, the swelling ratio is 1714%. This was supported by the discovery of ester bonds on functional group test results and there were many free space and fiber on hydrogel surface. Antibacterial material with silver nanoparticle addition was successfully obtained and had a biocidal activity to gram negative bacteria (E. coli).