The performance and emissions of an internal combustion engine (ICE) engine fuelled with two bio-diesels are experimentally measured and analysed according to ISO 8178 standard and compared with that of the petroleum diesel. Two types of bio-diesel, type A and type B (defined in Section 1) with their blends of B5, B10, B20, B50 and B100 are tested and analysed. This study found that the performance of both bio-diesel fuels reduces with increasing blend ratio, with a torque decrease of 5% for both bio-diesels, and a fuel consumption increase of 7-10%. This can be attributed to the lower energy content of bio-diesel when compared with petroleum diesel. For both the bio-diesels, some emissions were found to be higher than petroleum diesel, while some were lower. Nitrogen Oxide (NO(x)) emissions decreased by 14% for bio-diesel A, but increased by 17% for bio-diesel B. Carbon monoxides (CO) emissions were significantly reduced for both bio-diesel A and B, with reductions of 58% and 27% respectively. Hydrocarbon (HC) emissions were found to increase with increasing blend ratio for both bio-diesels, with an increase of 10% for bio-diesel A and 80% for bio-diesel B. Lastly, Carbon dioxides (CO(2)) emissions were found to increase, with an increase of 6% for bio-diesel A and 18% for bio-diesel B. The study clearly found that each of the bio-diesels has different scale of effect on ICE performance and emissions and hence, it is essential to test bio-diesels before it can be recommended for mass scale production and for commercial use in ICE. However, the study indicates that the two major pollutant gas emissions are generally reduced when using bio-diesel, therefore bio-diesel can be considered to be a more environmentally friendly, secure and renewable approach of obtaining energy in the long run. (C) 2011 Elsevier Ltd. All rights reserved.