To evaluate nutritive values of forages as rabbit feed resources by using in vitro digestibility and gas production techniques with inocula from caecal fluid, a study was implemented at laboratory of Cantho University, Vietnam. Fifteen forage samples including grasses, legumes and others were used to determine nutrient compositions, in vitro organic matter digestibility (OMD) and gas production volume (GPV) at different incubated times. The results showed that the caecal fluid of rabbits could be used as inocula for in vitro digestibility and gas production measurements. The in vitro OMD and GPV values had linear relationship to metabolizable energy and neutral detergent fiber (NDF) content with R² value >0.71. The in vitro GPV combined with crude protein and NDF had a close relation to in vitro OMD with R² value >0.90. It was concluded that the in vitro digestibility and gas production techniques by inoculum from caecum of rabbit had great potential to evaluate nutritive values of forages for rabbits.