The objective of this study was to evaluate the effects of replacing soybean meal and supplemental fat with extruded soybean, roasted soybean or a combination of extruded soybean and roasted soybean on performance of Holstein dairy cows. Eight multiparous and primiparous cows (113 ± 12 DIM, and 96 ± 20 DIM, respectively) were used in a replicated 4 × 4 Latin square design with 21 d periods. Treatments were: 1) 13.88% of diets DM as soybean meal (SBM); 2) 15.55% of diet DM as extruded soybean (ES); 3) 15.22% of diet DM as roasted soybean (RS), and 4) 7.69% extruded soybean and 7.69% roasted soybean (E+R). Diets were fed ad libitum as TMR with a concentrate to forage ratio of 60:40. Intake and milk yield were measured during d 14 to 21. On the last day of each experimental period, rumen fluid from the ventral sac was sampled 4 h after morning feed delivery using the rumenocentesis technique. On the last 5 consecutive days of each period, samples of TMR, and orts were collected daily for determination of PS. The PS of these samples was measured in triplicate using the Penn State Particle Separator () equipped with 3 sieves and a bottom pan. Dry matter intake, milk yield, and components of milk were similar for cows on all treatments ( P 0.05). Crude protein intake ( P = 0.015) and nitrogen intake ( P = 0.019) were affected by treatments. The digestibility of dry matter ( P = 0.006), organic matter ( P = 0.007), and crude protei ( P = 0.001), were affected by treatment, but treatments had no significant effect on ether extract digestibility ( P 0.05). Substitutions of rumen undegradable protein sources (extruded soybean and roasted soybean) for soybean meal reduced the urinary nitrogen ( P = 0.023), PUN ( P = 0.002), MUN ( P = 0.029), and tended to increase nitrogen apparent efficiency ( P = 0.133) significantly. Acetate and butyrate concentrations were not affected by treatments ( P 0.05), but propionate concentration tended to be affected by treatment ( P = 0.065), and the highest amount was for RS treatment. Treatments had significant effect on ruminal NH 3 N ( P = 0.039). Rumen pH, plasma glucose, triglyceride, albumin, total protein, cholesterol, and globulin concentrations were not affected by treatments ( P 0.050). % DM retained on 1.18 mm sieves was highest for SBM treatment ( P = 0.004), and it caused the pef 1.18 ( P = 0.031), and peNDF 1.18 ( P = 0.003) were highest for this treatment. In addition the X gm was not affected by treatments ( P 0.05). The time spent for eating, ruminating and total chewing activity were not influenced by treatment ( P 0.05), but eating time per kilogram of peNDF 1.18 was affected by treatments ( P = 0.020). Rectum temperature, and respiration rate were not affected by treatments ( P 0.05). In conclusion, replacing soybean meal and supplemental fat with extruded soybean and roasted soybean had no negative effect on performance of dairy cows while, it is expected to improve reproductive performance by reducing MUN, and PUN. Key words :Soybean meal, Roasted soybean, Extruded soybean, Performance, Dairy cows