The importance of dietary fiber in maintaining optimum bowel function has been shown in feedings studies, and many enteral formulas now contain dietary fiber, usually as soy polysaccharide (SP). Generally only total dietary fiber (TDF) values are given on the label or in product literature, with no indication of insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) content. Often product literature highlights the amount of SP contained in the formula, not the TDF. The method used to determine TDF content usually is not specified, making it impossible to compare products on a TDF basis. We compared the dietary fiber content of commercially available enteral formulas objectively to help clinicians make informed choices when selecting fiber-containing formulas. Fiber-containing formulas by suppliers were freeze-dried and total, water-soluble, and water-insoluble dietary fiber measured by the Association of Official Analytical Chemists (AOAC) approved method. TDF per 1000 mL ranged from 4.0 to 9.9 g for blenderized formulas and from 7.2 to 20.3 g in formulas containing SP. IDF values per 1000 mL ranged from 2.0 to 5.4 g for blenderized product, and the soy formulas ranged from 5.5 to 16.9 g. SDF values per 1000 mL ranged from 2.0 to 4.5 g in blenderized products, and in soy formulas SDF ranged from 1.7 to 3.8 g. Differences in physiological effects of fiber-containing enteral formulas may be because of differences in fiber composition.