Influences of the volume fraction and the type of aggregate on shrinkage in mortars and concretes made with an expansive cement were examined by using 10 cm x 10 cm x 30 cm prismatic specimens. It was found that the measured shrinkage strains of river sand mortars and crushed stone concretes were not so far from those calculated by the use of the formula derived by Pickett. In the lightweight aggregate mortars and concretes, measured shrinkage strains were found to be considerably smaller than the calculated ones. Large amounts of water retained in pores in the lightweight aggregate particles can account for the discrepancy. Strains within aggregate particles in the ordinary and the expansive cement concretes were measured by using the moM type electrical resistance strain gages inserted into the processed coarse aggregates. Some debonding seems to have occurred around the coarse aggregate particle during the process of expansion. Strains within aggregate particles and overall expansions of the concrete reinforced with steel bars were also measured. The results indicated that cracks occurred along the matrix-aggregate interface in the reinforced expansive cement concretes as well. The formation of the cracks leads to partial loss of restraint of aggregate particles against shrinkage during drying.