The optimal level of beet pulp (BP) inclusion in a meat-based dog diet and the effects of graded levels of dietary BP on fecal excretion responses and mean retention time of marked fiber in the gastrointestinal tract of the dog were evaluated using 30 female English Pointers assigned to isonitrogenous diets containing 0, 2.5, 5.0, 7.5, 10.0 or 12.5% BP (DM basis). Beet pulp replaced portions of dietary cornstarch. Digestibilities of DM and OM decreased by an average of 6% when comparing diets containing BP to the control diet, and quadratic and cubic responses were noted in digestibilities of fiber constituents (lower values at the 7.5 and 10.0% levels, higher values at the 2.5, 5.0 and 12.5% levels). Digestible energy (DE) and ME intakes (kcal/d) were not affected by treatment, but when expressed as a percentage of GE, values decreased (4.8% for DE; 6.2% for ME) linearly with increasing BP levels. Wet weight of feces increased (from 117 to 374 g/d) linearly as percentage of dietary BP increased. Frequency of defecation was higher (P less than .05) for dogs fed the diet containing 12.5% BP than for dogs fed the other diets (5.2 vs mean value of 2.8/24 h). Mean retention time of marked fiber decreased linearly (high value of 23.4 h for the 2.5% BP treatment, low value of 13.0 h for the 10.0% BP treatment) with increased level of BP. Beet pulp levels up to 7.5% of diet DM appear acceptable as a dietary fiber source in a meat-based canine diet.