The network common data form (netCDF) was created by Unidata at the University Corporation for Atmospheric Research to simplify data access and sharing in the atmospheric and geoscience science community. Even though the current full release of netCDF, known as netCDF-3, has proven to be successful, increasing data complexity and user demands for increased functionality have necessitated a new release of netCDF with improved functionality and the ability to store user defined data types. With these requirements in mind, Unidata created netCDF-4, which augments the functionality of netCDF-3 with more flexible ways to add data, better support for custom data structures, and simplified use of another more complex data model, known as HDF5. At present netCDF-4 interfaces exist for C and Fortran, however none exists for C++. This project's aim was to implement a C++ interface for netCDF-4. The netCDF-4 C++ interface was implemented as a thin layer on top of the netCDF-4 C interface; its design, however, allows all the functionality of a full C++ implementation. The netCDF-4 C++ interface will allow data providers and developers with a preference for C++ to take advantage of the new features netCDF-4 offers for creating portable, self-describing datasets. A prototype version of the C++ interface is available for evaluation and testing from http://www.unidata.ucar.edu/software/netcdf/netcdf-4. Comments should be directed to Ed Hartnett at ed@unidata.ucar.edu.