Roller-compacted concrete (RCC) is used throughout the world for new dam construction. In the United States, RCC is also used extensively for modifying dams with safety deficiencies including stability buttresses for concrete dams, overtopping protection for both concrete and embankment dams, and for constructing spillways. Rapidly placing RCC has an advantage for dam modifications which may only have a limited time to complete construction before placing the structures back in service. The Bureau of Reclamation has used RCC for several unique dam safety modifications. The Portland Cement Association (PCA) has been leading the design and construction industry by promoting the use of RCC in embankment dam overtopping protection since 1985. This paper will discuss the use of RCC for dam modifications including design and construction considerations for RCC construction and case histories of RCC dam safety modifications.