Technical Abstract: A filter bag analyses system for determining neutral and acid detergent fiber (NDF and ADF, respectively) and in vitro dry matter digestibility (IVDMD) were evaluated for use in forage breeding programs. In both filter bag systems, i.e. Ankom Fiber Analyzer and Ankom Rumen Fermenter systems, the forage samples are sealed in filter bags and the analyses are conducted on a batch basis rather than on an individual basis as in the conventional IVDMD and fiber analyses procedures. Smooth bromegrass (Bromus inermis Leyss.), switchgrass (Panicum virgatum L.), and forage sorghum (Sorghum bicolor (L.) Moench) samples were analyzed for NDF, ADF, and IVDMD using convention analyses and filter bag procedures. NDF and ADF values were 9% lower and IVDMD values were 7% higher using the filter bag system compared to conventional analyses. The method x entry interaction effects were usually not significant or were very small in comparison to method and entry effects. Spearman rank correlations were high and significant. These results indicate that the fiber bag analyses systems ranks forage samples from breeding programs in the same relative order as conventional analyses methods. The fiber bag method also has distinct advantages in terms of laboratory safety and labor and time management.