The purpose of this study was to identify pretending elements as they appeared in block play. We were also to determine if the pretend elements in block play differed between 3 years and 5 years old, and between boys and girls. The participants for this study were sixty-four 3-year-old children (36 were boys and 28 were girls) and sixty-eight 5-year-old children (32 were boys and 36 were girls). The analyzing tool of pretending elements in clay play (ATPE) developed by Han & Park (2010), was used to evaluate the pretending elements which appeared in block play. Twelve undergraduates majoring in early childhood care and education were trained to observe and record the pretending elements in block play. One hundred and twenty six (126) children were divided into 25 groups of 5 children each, with one group of six. They participated in 5 block play sessions twice a week. The duration of each play session was 40 minutes. T-tests were used to examine the differences in the pretending elements by gender and age. The children participated more in ‘projective pretend play’ than ‘self-subjective pretend play’. In sub-items of self-subjective pretend play, ‘pretending to play a role’ appeared most frequently in both gender. Whereas, in sub-items of ‘projective pretend play’, the most frequently appeared pretending element was ‘pretending play with an object’, especially boys did more ‘projective pretending with an object’ than girls. There were no differences in the pretending elements by age. This result indicated that constructive play was not just to make some constructions with materials but closely related with symbolism. It could be also seen that the pretending elements appearing in constructive play were differ from depending on the materials in the play. By providing appropriate and various materials to children, teachers and parents should guide and stimulate the constructive play with pretending.