Microfluidics-based biochips offer exciting possibilities for highthroughput sequencing, parallel immunoassays, blood chemistry for clinical diagnostics, DNA sequencing, and environmental toxicity monitoring. The complexity of microfluidic devices is expected to become significant in the near future due to the need for multiple and concurrent biochemical assays on multifunctional and reconfigurable platforms. This paper presents early work on topdown system-level computer-aided design (CAD) tools for the synthesis, testing and reconfiguration of microfluidic biochips. Synthesis tools map behavioral descriptions to a droplet-based microfluidic biochip and generate an optimized schedule of assay operations, the binding of assay operations to functional units, and the layout and droplet flow-paths. Cost-effective testing techniques lead to the detection of manufacturing defects and operational faults. Reconfiguration techniques, incorporated in these CAD tools, can easily bypass faults o...