The inclusion of modular functional units is often used as an example of how environmental considerations can be incorporated in the design stage of electronic products. The assumption is that the functional units can can be reused at end of life to perform the same task in a different product. The environmental benefit from this practice is only accrued if the feedback loop from recovery to remanufacture is completed. The barriers to the completion of this loop are numerous and concern compatability, reliability, functionality, flexibility and cost inter alia. This paper discusses the concept of modular digital electronic circuits based on programmable logic device technology and examines their suitability for use in the scheme of an overall Eco-design methodology based on the re-use of such modular units. A comparative streamlined life cycle assessment between this methodology and conventional digital electronics is also conducted to inspect the environmental benefits across the whole life cycle. © 2006 IEEE.