Abstract An in vitro dry matter disappearance (IVDMD) study and two 138-day feeding trials were conducted to evaluate wet potato and corn chipping by-products as feeds for beef cattle. In Trial 1, IVDMD was measured for simulated diets containing either potato filter cake (PFC) or corn centrifuge solids (CCS). The basal diet consisted of corn silage and urea (13% total dietary crude protein). Potato and corn by-products separately replaced corn silage in 10 percentage unit increments of dietary dry matter (DM). When CCS replaced corn silage, IVDMD increased 2·07 percentage units for each increment in the dietary by-product level. The corresponding value for PFC was 0·47 percentage units. In Trial 2, yearling heifers (255 kg) fed barley silage based diets containing 7, 15 and 30% mixed potato and corn by-products (DM basis) had similar rates of gain (1·21 to 1·25 kg day −1; P > 0·05). Daily DM intakes (kg) and DM: gain ratios were 8·39, 6·93; 8·52, 7·04; 8·04, 6·43, respectively, for the three diets. In Trial 3, barley silage based diets containing 0, 9 and 18% mixed potato and corn by-products were fed to yearling heifers (246 kg). Average daily gains ranged from 1·13 to 1·18 kg (P > 0·05). Daily DM intakes (kg) and DM: gain ratios were 8·81, 7·78, 9·16; 8·31, 7·35, respectively, for the three diets. The results of these experiments suggest that wet potato and corn chipping by-products may replace up to 30% of dietary DM in beef cattle finishing diets without decreasing animal performance.