Currently, there are a number of research data service providers that allow deposit of research data or gather metadata for research data housed elsewhere. Examples include Datacite (http://www.datacite.org/), Dataverse Network (http://thedata.org/), Dryad (http://datadryad.org/), and FigShare (http://figshare.com/). These services make use of a broad range of metadata practices and elements. The objective of this study is to examine the metadata standards and formats used by a select number of research data services to address the following specific research questions: 1) What is the number and nature of metadata elements available? 2) Do any of the services provide research data specific metadata elements in addition to common metadata elements? 3) Do the research data management services adhere to widely recognized metadata, interoperability and preservation standards? 4) What research data repositories benefit from and promote controlled vocabularies for subject description and access? 5) Is there support for unique identifiers (e.g., DOIs)? 6) What kind of metadata assistance (documentation, etc.) is provided? 7) What metadata elements are common and different across these services? The results of this study will contribute to a better understanding of the development and application of metadata in research data services as well as to the development of an interoperable research data environment.