The paper presents an analysis of the emission level from a heavy-duty truck of the GVW of 12,000 kg. The exhaust emission tests were performed under actual traffic conditions in the area of Poznań. For the tests portable exhaust emission analyzers SEMTECH DS and AVL Micro Soot Sensor were used. The characteristics of the exhaust emission components have been determined in relation to the engine speed and load as well as vehicle parameters (speed and acceleration). The paper includes an analysis of the engine operating conditions as well as the range of engine speeds and engine loads. The vehicle fuel consumption was also determined through the carbon balance method. Based on the obtained values of the emission of CO, NOx and PM, the emission indexes were determined that provided information on the relation of the measured emissions to the levels specified in the EEV standard. The emissions of all the exhaust components, except NOx were lower than the EEV limits. Consequently, it appears that for this type of vehicles, NOx is the most troublesome exhaust component that should be monitored in everyday operation.