The paper describes the measurement of PM emission from an excavator engine under actual operating conditions. The exploration of the relations between the engine operating parameters and its emissions requires measurements under actual conditions of engine operation. The specificity of the emission measurements, PM in particular, requires technologically advanced measuring devices. The situation gets even more complicated when, beside the PM mass. The particle size distribution and number (PN) also need to be measured. An important technical issue is the difficulty in fitting the measurement equipment in/on the vehicle in operation (e.g. excavator), which is why the presented investigations were carried out in a laboratory under simulated operation. The laboratory technicians applied load to the engines through the excavator hydraulic system. During the tests, the authors attempted to reflect the operating conditions (prerecorded engine speeds and loads when the excavator operated in the field). The paper presents the results of the investigations on the emission of particulate matter (PM). The performed measurements have shown the Particle mass, number and size distribution. For the measurement, the authors used modern technology analyzers: Micro Soot Sensor by AVL and Engine Exhaust Particle Sizer by TSI. To complement the research, measurements of other exhaust components have also been carried out.