The objective of this study was to evaluate effect of faeces sources used as inocula on in vitro gas production for future applied studies. The experiment was conducted at Department of Animal Sciences, College of Agriculture of Can Tho University. It was a factorial design (5*4) with 4 replications. Factor 1 was five sources of faeces from buffalo (BF), cattle (CF), pig (PF), goat (GF) and rabbit (RF). The factor 2 was 4 feeds including Para grass (PG), sesbania grandiflora (SG), rice straw (RS) and pineapple peel (PP). The measurements of gas production were at 3, 6, 9, 12, 24, 48, 72 and 96 h. The results showed that gas production of five source of faeces were significantly different (P<0.05) among them. At 12, 24, 48 and 96 h gas production of GF was the highest values and significantly higher (P<0.05) compared to BF and RF. The in vitro gas production of PP was the highest values and significantly different (P<0.05) to PG, SG and RS at 24, 48 and 96 h of incubation. The conclusion was that all faecal sources of the study could be used as inocula for in in vitro gas production and goat faeces was the most potential for applications.