Tensile creep behaviour of the fine grained Fe-Mn binary alloys containing 0.42-1.21 wt.% Mn has been investigated in the temperature range from room temperature to 475 K under 10-50 MPa. Tensile tests are carried out with a constant cross-head speed under uniaxail load at a strain rate 10(-4) s(-1). Stress exponent and activation energy are determined to clarify deformation mechanism. The obtained variation of steady state creep rate with respect to the applied stress for Fe-Mn binary alloys exhibits two distinct regimes at about 20 MPa, indicating a possible change in creep mechanism. The average stress exponent is approximately 2.2, which is a characteristic of grain boundry sliding in the alloys. The activation energy for plastic flow varies from 135 to 92 kJ/mol, depending on the Mn content.