Aims: To use molecular beacon based nucleic acid sequence-based amplification (NASBA) to develop a rapid, sensitive, specific detection method for norovirus (NV) genogroupII (GII). Methods and Results: A method to detect NV GII from environmental samples using real-time NASBA was developed. This method was routinely sensitive to 100 copies of target RNA and intermittent amplification occurred with as few as 10 copies. Quantitative estimates of viral load were possible over at least four orders of magnitude. Conclusions: The NASBA method described here is a reliable and sensitive assay for the detection of NV. This method has the potential to be linked to a handheld NASBA device that would make this real-time assay a portable and inexpensive alternative to bench-top, lab-based assays. Significance and Impact of the Study:The development of the real-time NASBA assay described here has resulted in a simple, rapid (< 1 h), convenient testing format for NV. To our knowledge, this is the first example of a molecular beacon based NASBA assay for NV.