AbstractUniaxial creep tests at 80 MPa with different temperatures and at 600°C with different loads were carried out for a 12%CrMoV martensitic steel. The creep strain behaviour was analysed using an ana lytical expression where. the creep strain rate is proportional to the exponential of the creep strain. The creep curves, rupture times and strains could be well reproduced. The observed and predicted rupture times satisfied the Monkman-Grant relationship.