Current fMRI neuroimaging software programs offer the researcher a wealth of analysis methods and tools. However, the incompatibilities in user interface, data format, and computing environment in these tools make it difficult if not impossible for most researchers to take advantage of the full set of resources available for neuroimaging analyses. We describe a graphical computing environment, Functional Imaging Software Widgets (fiswidgets), which was developed to address these interoperability and usability problems. This environment provides a desktop style framework into which 100 subcomponents from a number of widely used fMRI analysis software packages (e.g., AFNI, AIR) are incorporated. It is an open-source, extensible environment available for reuse and modification by other software developers. A discussion of the design criteria (open architecture, modularity, wrapper technology, commercial utilities) that support such loosely integrative computing environments, and the problems entailed in maintaining them (development overhead, distribution logistics, format incompatibilities, graphics vs scripting tradeoffs, and appropriate acknowledgment of software developers) follows.