An international comparison in the pressure range 20 MPa to 100 MPa has been carried out under the auspices of the high-pressure working group of the Comité Consultatif pour la Masse et les grandeurs apparentées (CCM). The work was initiated in 1981 and completed in 1989. The standards laboratories of seventeen countries participated in the comparison. The results of the laboratories which took part in the first three phases have been published in a comparative form in Metrologia. This paper presents the complete results and the main conclusions of the work.