Betaine, a co-product of sugar-beet processing, can be used to feed cattle. Because high-grade betaine (>90% pure; DM basis) is expensive, feed-grade products with lower betaine concentration are typically used in cattle rations. However, there is limited information on the impact of feeding the feed-grade betaine products on rumen fermentation characteristics. Therefore, our objective was to compare in vitro rumen fermentation characteristics of a high-grade betaine (97% purity) to a feed-grade betaine product (32% purity). The Ankom gas production system was used (Ankom Technologies, Macedon, NY) to determine the in vitro fermentation characteristics of both products at the same inclusion level. Three dietary treatments were used: control (CON) with no betaine added, high-grade crystalline betaine (CRYS), and feed-grade liquid betaine (LB50) at 0.50% of diet DM. The study was a completely randomized design and each treatment was added to 2 Ankom modules, which contained 1.5 g of TMR, 15 mL rumen fluid, and 45 mL McDougall’s buffer. Two Ankom modules were also used as blank/run. A total of 3 runs were conducted. Data were analyzed using the mixed procedure of SAS. Crystalline betaine had a greater CP content compared with the liquid betaine (72.8 vs 56.7% DM). Total volatile fatty acid production tended to be greater in LB50 vs CRYS (140.23 vs. 109.14 mM respectively, P = 0.09) while no differences (P > 0.1) were detected in the molar proportions of acetate, propionate, butyrate, isobutyrate, valerate, isovalerate, and caproate, which averaged 49.15 ± 0.81, 29.67 ± 0.69, 13.78 ± 0.51, 1.27 ± 0.04, 3.50 ± 0.12, 2.06 ± 0.09, and 0.58 ± 0.07% respectively. Final pH did not differ (P = 0.27) among treatments and averaged 6.20 ± 0.02. Similarly, in vitro true DM digestibility and methane production did not differ (P ≥ 0.15) among treatments. In summary, the lack of differences in in vitro fermentation characteristics between an expensive high-grade and a lower-grade betaine product suggests a similar feeding value when fed at the same dietary inclusion rate.