A quadricycle is a vehicle that has become increasingly popular recently. One of the main advantages of a quadricycle is its ability to ride on bad roads or off-road. Quadricycles can be used for a wide variety of purposes - for recreational rides, in agriculture or as a vehicle for certain services. There are different types of quadricycles according to their design and purpose. They can be driven by two wheels or all four, can be designed for one driver only or can be adapted to carry a passenger. Due to their size, quadricycles often have relatively poor stability parameters, i.e., they can roll over. Considering that they are also designed for off-road riding, rollover is a common type of accident. The stability parameters of vehicles that determine the possibility of rollover are very important, and the safety of the trip depends on them. Rollovers of quadricycles are particularly dangerous because they usually do not have any active or passive safety measures that reduce the risk of rollover. Many stability parameters of all vehicles, which determine their resistance to rollover, are closely related and depend on the dimensions of the vehicle and the location of the centre of mass. The article investigates the stability of the CF MOTO CFORCE 450L quadricycle. The experimental method determines the location of the centre of mass of the analysed vehicle, both unloaded and with the driver. A mathematical model for determining the location of the centre of mass is developed and validated by comparing the results obtained with the results determined by the experimental method. The developed mathematical model allows for the accurate determination of the location of the vehicle’s centre of mass and its changes under different loading conditions of the quadricycle. In this model, the masses and positions of the driver, passenger and/or additional luggage can be easily changed. Based on the coordinates of the centre of mass of the quadricycle obtained by the computational model, the stability of the analysed vehicle is assessed. The following stability parameters of the quadricycle were calculated - critical speed in turns, critical angles of uphill and downhill slopes in the longitudinal direction, and dangerous slopes of the road in the transverse direction. The results obtained showed that the quadricycle CF MOTO CFORCE 450L is the most stable when driven only by the driver of the vehicle, and an additional passenger and/or luggage in all cases reduces the stability of the analysed vehicle.