This paper presents a new fault detection technique for digital micro-fluidic based biochips. Due to recent advances in microfluidics, digital micro-fluidic biochips are revolutionizing laboratory procedures, e.g., biosensing, clinical diagnostics etc. Because of the underlying mixed-technology and mixed energy domains, biochips exhibit unique failure mechanisms and defects. Off-line and on-line test techniques are required to ensure system dependability. In this paper, a new technique is presented to traverse all the cells and cell boundary, for the purpose of detecting a single fault within the bio-chip. Experimental results show that the proposed technique improves the fault detection time to a great extent. © 2010 IEEE.