Persistent unique identifiers provide a means of long-lasting identification of digital objects that are global, standardized, and widely used in the digital environment and can provide information on the object, regardless of where the object is located. Persistent unique identifiers include DOIs, ARKs, Handles, and ORCiDs. Assigning persistent unique identifiers to data helps to provide a method to locate data in the the vast amounts of research data generated on a daily basis. DataCite is one initiative that provides an opportunity for research organizations to assign DOIs to their datasets. Assigning DOIs allow for a particular dataset to be persistently identified so that it can always be located and cited appropriately. While information about a digital object may change over time, including where to find it, its DOI name will never change so it can always be found. Librarians can help researchers assign persistent unique identifiers to data by providing insight on the process of assigning and applying the identifiers.