This study investigated the effects of dietary glycerin supplementation on rumen fermentation, blood metabolites, growth performance, and carcass characteristics in Korean cattle steers. Steers (n=15; average 30.5 ± 0.2 months old; 607 ± 15.2 kg of body weight [BW]) were equally assigned to three groups: 1) control (wheat bran supplementation only), 2) 6.4% glycerin supplementation (glycerin-absorbed wheat bran), and 3) 8.7% corn starch supplementation (corn starch + wheat bran) group. Both glycerin and corn starch supplementation group received same amount of energy. A concentrate (the amount of 1.35% of BW) and 1.0 kg of oat straw were individually fed twice daily for 4 months. Supplementation was done with top-dressing during concentrate feeding. Steers were weighed at 4 weeks interval, and blood and rumen fluid were collected at 8 weeks interval. Steers were slaughtered at average 34.3 ± 0.2 months old, and longissimus thoracis (LT) samples were collected and analyzed for beef characteristics. Data were analyzed by ANOVA using the GLM Procedure (Proc GLM) in SAS software. Neither glycerin nor corn starch supplementation affected (P > 0.05) feed intake, average daily gain, and feed efficiency. Circulating glucose concentrations were higher (P < 0.05) in glycerin group compared with two other groups at 16 weeks, and triglyceride and non-esterified fatty acid concentrations were unaffected by both supplementation. The pH and acetate, propionate, and butyrate concentrations in rumen fluid were unaffected by both supplementation. Neither glycerin nor corn starch supplementation affected (P > 0.05) carcass weight and quality grade. Neither glycerin nor corn starch supplementation affected (P > 0.05) chemical composition, meat color parameters (CIE a* and b*), glycogen content, reducing sugar content, and sensory traits of the LT samples. In conclusion, dietary crude glycerin supplementation have not affected blood and rumen characteristics, growth performance, and carcass characteristics in Korean cattle steers.