A prototype portable near-infrared spectrometer was designed for the determination of moisture, total-N, organic-N and ammonium-N in dairy manures. The instrument is based on filters selected from spectra (400 to 2498 nm) obtained on a scanning monochromator (NIRSystems model 6500). The prototype instrument may contain up to 20 filters which allows for testing and implementation for other manure types. Preliminary testing demonstrated that the instrument is capable of providing accurate estimates of the applicable analytes in an on-farm environment. Further testing on both dairy and poultry manures is in progress. This instrument demonstrates the feasibility of designing portable near-infrared filter based instruments for on-farm manure analysis.