This paper proposes the use of on-chip monitor circuits to detect process shift and process spread for post-silicon diagnosis and model-hardware correlation. The amounts of shift and spread allow test engineers to decide the correct test strategy. Monitor structures suitable for detection of process shift and process spread are discussed. Test chips targeting a nominal process corner as well as 4 other corners of “slow-slow”, “fast-fast”, “slow-fast” and “fast-slow” are fabricated in a 65nm process. The monitor structures correctly detects the location of each chip in the process space. The outputs of the monitor structures are further analyzed and decomposed into the process variations in threshold voltage and gate length for model-hardware correlation. Path delay predictions match closely with the silicon values using the extracted parameter shifts. On-chip monitors capable of detecting process shift and process spread are helpful for performance prediction of digital and analog circuits, adaptive delay testing and post-silicon statistical analysis.