The objective was to determine whether sugar inclusion and the type of sugar (lactose; LAC or sucrose; SUC) as a replacement for starch influences ruminal glucose and short-chain fatty acid (SCFA) uptake by the rumen epithelium. Eighteen Suffolk × Arcott wethers were randomly assigned to 1 of 3 diets: control (CON), LAC (whey permeate), and SUC (molasses). Sugar content was 6% of DM for LAC and SUC and partially replaced barley grain ensuring NSC was balanced among treatments. After 31d, lambs were killed and the caudal-ventral blind sac was collected and washed using a pre-heated buffer solution. The tissue was then stripped of the underlying muscular layer and mounted in Ussing chambers under short-circuit conditions. The uptake of ¹⁴C-butyrate, ¹⁴C-propionate and ³H-acetate under non-inhibited conditions and conditions that inhibit protein-mediated uptake were measured. The uptake of ¹⁴C-glucose was evaluated without inhibition and when phlorizin (0.5 mM; inhibitor of sodium-linked glucose transporter; SGLT-1), or phloretin (0.5 mM; inhibitor of facilitated glucose transporters) were included. Data were analyzed using PROC MIXED in SAS and contrasts used to evaluate the effect of sugar (CON vs. sugar) and type (LAC vs. SUC). Acetate uptake was reduced (P = 0.04) for lambs fed sugar due to a reduction in passive diffusion (P = 0.02), whereas protein-mediated uptake did not differ (P = 0.24). Propionate uptake was not affected by sugar inclusion; however, lambs fed LAC tended (P = 0.098) to have greater propionate uptake and had greater (P = 0.043) protein-mediated propionate uptake than those fed SUC. Lambs fed LAC tended (P = 0.10) to have greater protein-mediated and passive uptake of butyrate than those fed SUC. Glucose uptake was increased 1.7 times for lambs fed sugar compared with those fed CON (P = 0.012). The SGLT-1 uptake tended to be greater for lambs fed sugar than those fed CON (P = 0.09). The results of this study indicate that the type of sugar included in diets may influence SCFA and glucose uptake by the rumen epithelium.