Hydrogenated Vegetable Oil (HVO) diesel fuels have the potential to provide a reduced carbon footprint for diesel engines and reduce exhaust emissions. Therefore, it is a strong candidate for transport and diesel powered machines including electricity generators and other off-road machines. In this research, a waste cooking oil derived HVO diesel was investigated for its combustion and emission performance including ignition delays, size segregated particulate number emissions and gaseous emissions. The results were compared to the standard petroleum diesel. A EURO5 emission compliant three litre, direct injection, intercooled IVECO diesel engine equipped with EGR was used which has a maximum power output of 96kW. The engine was equipped with an integrated DOC and DPF aftertreatment system. Both the upstream and downstream of the aftertreatment emissions were measured. The tests were conducted at different RPM and loads at steady state conditions. A DMS500 particle size measurement instrument was used for measuring particles between 5 nm and 1000nm. The engine was instrumented with a number of thermocouples so that the engine conditions were closely monitored. Gaseous emissions were measured using a HORIBA 7100 series gas analyzer. The results showed that HVO reduced particulate numbers significantly at the upstream of the aftertreatment system. The particle number emissions were not much different between HVO and standard diesel at the downstream of the aftertreatment system due to the low particle number concentrations.