Whole–plant maize silage dorms the basis of winter rations for the vast majority of dairy and beef cattle production in Uruguay. Microbiological examination of silage is of little value in gauging the outcome of silage, and so chemical analysis is more reliable and meaningful indicator of quality. Chemical assessments of the principal fermentation products provide an unequivocal basis on which to judge quality. Silage fermentation and chemical composition are important to preservation of forage with respect of feeding value and animal performance. Many of the important chemical components of silage must be assayed in fresh (wet presentation) or by extraction of the fresh material, since drying either by heat or lyophilisation, volatilises components such as acids or nitrogenous components, or effects conversion to other compounds (fibre and carbohydrates) (Abrams et al., 1987). Chemical and biological methods for assess maize silage quality are laborious and considered to slow to be used for routine analysis of large number of forage samples. Near infrared reflectance spectroscopy (NIRS) is increasingly used as a rapid, accurate method of evaluating chemical constituents in cereals and dried forages. The objective of this study was to determine the potential of NIRS to assess the chemical composition of dried maize silage samples for advisory purposes.