Common data structures associated with procedurally-oriented software, such as Fortran COMMON blocks, are translated into object-oriented (OO) classes. Procedurally-oriented software modules are reduced in complexity by extracting an appropriate number of sub-modules from the original source code so that the original module and each extracted module is below a predetermined complexity level, if possible. The original module and extracted modules are assigned to an object-oriented class based upon a measure of each modules' association to the respective class' data members, where the assigned modules are then translated into object-oriented methods. This approach greatly reduces overall system development time and costs by automatically generating maintainable object-oriented code based upon translated procedurally-oriented source code. Man-hours are further saved by automatically documenting the newly generated object-oriented classes and by automatically generating test suite files for use in verifying and troubleshooting the automatically generated object-oriented classes.