In the present study, we explore aspects of Greek primary school children's representations about the urban environment through the use of drawings and their relation to sustainability. For that purpose, 104 children, aged 9-12 (4th and 6th grades), were asked to make two drawings of their town: one as it is now and another as they would like it to be. Drawings were analysed using pre-defined categories of urban sustainability and were statistically analysed using SPSS. Results revealed a serious gap in knowledge regarding energy and aspects of local development tied to sustainability in the current and future state of the children's towns. Although the most popular characteristics in the children's drawings were associated with the environment, the majority of children illustrated issues related to society. Evidence indicated an age-related progression of representations related to sustainability in the urban environment, at least concerning the topics of natural environment, infrastructure and the realization of problems caused by air pollution and municipal waste generation.