This study aimed to investigate the effects of increasing concentrate levels in the diet on intake, digestibility, ruminal fermentation and nitrogen retention in non-lactating goats. The repeated measures study used 3, 12-month-old, non-lactating crossbred Saanen goats (♂Saanen×♀ Bach Thao) weighing 30.2±1.25kg. Each experimental period lasted 15 days. Goats received a diet consisting of 75:25 forage [F]: concentrate [C] from d1 to d15 (C25) followed by 55:45 F:C (C45) from day 16 to day 30, and lastly a 35:65 F:C from day 31 to day 45 (C65). The concentrate was mixed at the farm and contained 18.5% crude protein. Samples were collected during the last 4 days of each period. Statistical analysis was performed using PROC MIXED with goat as random effect, while F: G ratio was the fixed effect. The results showed that increasing the level of concentrate in the diet linearly increased DM intake (P3-N (P