Technical Abstract: The decline of the U.S. textile industry has led to the dramatic increase in the export of U.S. cotton. Improved quality measurement systems are needed to successfully compete in the global marketplace. One key need is the development of new breeder/producer quality tools for field and at-line measurements, resulting in the vertical integration of the cotton quality chain from the cotton field to final fabric. Recent advances in portable Near Infrared (NIR) instrumentation could result in improved, rapid, and precise quality tools for laboratory and breeder analyses. A program was initiated to determine the capability of NIR analyzers to monitor the key cotton fiber property of micronaire for laboratory, at-line, and field measurements. Previous investigations had demonstrated the capabilities of portable NIR instrumentation to rapidly, precisely, and accurately measure the micronaire of cotton fiber (“lint”) samples in a controlled environment laboratory. Micronaire is a combination of the cotton fiber’s maturity and fineness (linear density). A program was implemented to expand the NIR measurement of cotton micronaire by portable NIR instrumentation from the laboratory to a non-laboratory location—the cotton field. Field trials for micronaire on cotton bolls in or near the cotton field were performed at four locations. Spectral evaluations demonstrated overall good NIR spectral agreement between laboratory and field measurements of micronaire with the portable NIR analyzer. Two field sampling systems were developed—plant measurements (cottons measured directly in the cotton field) and vehicle measurements (collected cottons measured at the vehicle in the field or at a nearby building). The field NIR measurements were fast (< 2 minutes per sample) and easy to perform. Distinct NIR micronaire differences were detected between cotton varieties and bolls with known HVI micronaire differences. The comparative results for the field measurements (cottons with seeds present) of cotton micronaire were very encouraging, as the trends in the HVI micronaire (Low-Medium-High) were correctly identified for 80% of the samples. The rapid and accurate laboratory measurement of cotton fiber micronaire trends at the cotton field with portable NIR instrumentation was demonstrated.