The deformation kinetics analysis of room temperature creep of high purity iron indicates two rate controlling mechanisms. The first of these is predominant during the initial part of the creep process and the second in the latter part when the internal stress increases and therefore the effective stress decreases. It is suggested that these mechanisms are associated with the overcoming of the Peierls-Nabarro stress field by the formation of a double kink and the lateral spreading of the kink. Strain rates diminishing to zero are believed to be a possible result of non-negligible backward activation over the double barrier system. It is shown that, for the proposed system of two consecutive barriers, the limiting strain and the limiting effective stress at which the rate becomes zero are proportional to the activation parameters of the kinetics term associated with the backward activation over the double barrier system. This also indicates that the effective stress is not necessarily zero for zero strain rates. A model of exponential strain dependence of the dislocation density has been proposed. The use of this model in the deformation kinetics description explicitly includes the effects of the initial dislocation density, dislocation multiplication, temperature, the initial effective stress and the work hardening coefficient on the calculated creep behavior. Results from this model indicate that the observed sharp levelling off may be due to dislocation multiplication.