This study was carried out to investigate the strength behavior of cemented sludge reinforced with cornsilk fiber considered as a by-product from corn. Hence, a series of unconfined compression test was conducted at different levels of water, cement, and fiber content. Water contents considered in this study were 40, 50, and 60%; cement content used for sludge stabilization was changed from 5 to 40 kg/m 3 ; meanwhile, fiber content was used at different levels from 5 to 30 kg/m 3 . In addition, the relationship between failure strength and the amount of water, cement, and fiber was investigated in the present work. The experiment results showed that there was an improvement in failure strength, failure strain, ductility, and stiffness with fiber inclusion. Besides, stiffness improvement was based on the amount of cement used. The relationship between failure strength with and without fiber inclusion and water, fiber, and cement content was described as following power or exponential function with a strong correlation coefficient. It was concluded that there was a good performance of cornsilk fiber in reinforcing cemented sludge. Furthermore, the utilization of waste material to modify soft soil or sludge will bring about many benefits not only for geotechnical engineering but also for the environment and social economy.