Synopsis Heat curing at temperatures up to 65°C reduced the creep and shrinkage of ordinary Portland cement pastes having a water/cement ratio of 0·47. Strain measured after unloading and after rewetting indicated that the reductions were primarily associated with the irrecoverable components of creep and shrinkage. The reductions did not correlate with differences between the combined water content or the capillary porosity of the cement pastes, but they were associated with differences in the extent of silicate polymerization within the cement hydrate. Elastic strains, creep-recovery strains and cube strengths of the cement pastes were not noticeably affected by the extent of silicate polymerization.