The ability of diet to affect rumen morphological development in calves has been known for many years. Underlying mechanisms remain unknown but are linked to ruminal VFA production and absorption. VFA production from a given diet is greatly influenced by diet composition, which may lead to differences in development of the rumen. The objective of this pilot-scale study was to determine the effect of diet composition on: calf BW and stature, rumen pH, VFA, lactate, and 3 measurements of rumen morphology. Eight neonatal Holstein bull calves were randomly assigned to one of 2 dietary treatments: high starch:low NDF pelleted starter (HS; n = 4; 19.7% CP, 26.7% starch, 23.6% NDF DM basis) or high NDF:low starch pelleted starter (HN; n = 4; 20.9% CP, 9.5% starch, 36.5% NDF DM basis). Starter grain and water were offered freechoice from birth and milk replacer (22.0% CP, 20.0% fat as-fed basis; 566 g DM/d) was fed twice daily at 13% solids. Calves were individually housed; feed intake was recorded daily. Calf BW, stature measurements, and oresophageally-obtained rumen content samples were collected from each calf weekly. All calves were euthanized at 7 wk of age to collect rumen morphology measurements. Data were analyzed by ANOVA using the MIXED procedure in SAS. There were no differences in BW, stature, or DMI measurements between treatments. Mean rumen pH throughout the 7 wk trial was lower for HS compared with HN calves (P = 0.006; 5.37 ± 0.08 and 5.81 ± 0.07, respectively). Mean acetate, propionate, butyrate, L-lactate, and D-lactate throughout the 7 wk trial were not affected by treatment (59.60 ± 3.42 mM, 37.15 ± 3.04 mM, 14.48 ± 3.97 mM, 6.02 ± 1.22 mM, and 5.27 ± 1.00, respectively). Treatment did not affect full or empty rumen mass (6.20 ± 0.93 kg and 1.12 ± 0.13 kg, respectively), ratio of absorptive surface to muscle (2.68 ± 0.39), or 2-dimensional surface area of papillae (4.56 ± 0.70 mm²). Feeding calf starters of 2 drastically different compositions did not affect overall calf or rumen growth. These findings support the idea that composition of diet may not influence the necessary changes in rumen fermentation that would alter rumen growth in calves.