Creep deformations and creep buckling times are obtained foraxisymmetric shallow spherical shells with and without initial imperfections. For nonlinear creeps, both strain-hardening and time-hardening rules are employed in the analysis;results indicate that strain-hardening yields better estimates of shell life than time- hardening. Results also show that the initial imperfection plays an important role in shortening shell creep buckling times. When compared with the experimental data of test specimens which possess very small departures from sphericity, it is observed that, in order to have a satisfactory prediction on both creep buckling times and creep deformations, in addition to fully taking into account the presence of initial imperfections, the analysis should adopt a mathematical creep model which includes not only the primary and the secondary creep but also the tertiary creep.