We study the presenteeism of employees in the public and private sectors to determine whether there is a link between this over-effort and their prosocial motivation. Using a counting model, we show that the prosocial motivation of employees does indeed generate a donated labour in the form of presenteeism, but this desire to work is the same for public and private sector employees. Moreover, in the absence of this motivation, average presenteeism in the public sector would be lower than in the private sector, since employees in this sector being encouraged to do so by other means than public employees.