Technical Abstract: Microwave blanching of peanuts has been proposed as an attractive alternative to traditional techniques of blanching, due to energy and time savings. However, the periodic occurrence of a processing-related off-flavor has been reported. This study examined the effect of processing factors during microwave blanching on the moisture content and sensory characteristics of the peanuts. Peanuts reached a range of internal temperatures during microwave blanching treatments between 4 and 11 minutes. A total offnote attribute was introduced to the peanut lexicon and was successfully used to differentiate the effects of microwave treatments. The microwave-associated off-flavor was related (but not identical) to cardboardy/stale flavor, and was inversely related to the positive flavor attributes roasted peanutty, sweet aromatic, and sweet taste. Peanuts reaching the highest internal temperatures and greatest moisture losses during blanching exhibited the most total offnote flavor. For maximum quality, microwave blanching for 8 minutes without air circulation is recommended.