Common Biometric Exchange Formats Framework (CBEFF) provides a standardized set of definitions and procedures that support the interchange of biometric data in standard data structures called CBEFF biometric information records (BIRs). CBEFF permits considerable flexibility regarding BIR structures and biometric data content, but does so in a way that makes it easy for biometric applications to evaluate their interest in processing a particular BIR. At its conceptually simplest, standard CBEFF data structures promote interoperability of biometric-based application programs and systems by specifying a standardized wrapper for describing, at a high level, the format and certain attributes of the content of a BIR. The initial versions of CBEFF were developed by the National Institute of Standards and Technology (NIST) and the Biometric Consortium. The CBEFF specification published by NIST in April 2004 (NISTIR 6529-A) was proposed as the basis for the development of formal national and international CBEFF standards. Since then, American National Standards and International Standards (ISO/IEC) have been published. Development continues on a new generation of CBEFF standards. The paper describes the main characteristics of CBEFF, emphasizing the value of CBEFF data structures in open and complex biometric systems, especially in cases where the system must cope with a wide variety of biometric data records, some of which may even be encrypted. It also discusses early work on CBEFF standardization as well as, recent and ongoing standardization efforts.