SAS® Clinical Data Integration (CDI) is built on the idea of transforming source data into CDISC standard domains such as SDTM and ADaM. However, you can also define custom data standards to use within CDI. This paper describes several scenarios for using custom data standards, such as incorporating company-specific requirements, developing therapeutic area or compound level domains, and even using study-specific data standards. This paper also describes in detail how to set up the required data sets to define a custom data standard, register the custom data standard with SAS Clinical Standards Toolkit (CST), and import the custom data standard into SAS Clinical Data Integration. In addition, best practices are discussed for both managing the security of SAS Clinical Standards Toolkit Global Library that is central to the SAS Clinical Data Integration application and for the overall process of developing custom data standards.