The purpose of this article is to explore day care attendants' comprehension of the concept of sustainable development (SD) and to analyse the associated pedagogical practices at their place of work in pre-schools. The empirical data comprise written exam reports from 32 practising day care attendants attending an in-service education course. The participants study early childhood education (ECE) part time at Mälardalen University, Sweden, and the rest of their time they work in their pre-schools. The analysis was based on a qualitative content analysis approach, and the results show a multi-faceted understanding of the concept. SD was seen as a holistic approach, an environmental issue or a democratic issue. The article explores how these different ways of approaching the concept relate to different attitudes and day-to-day practices in the pedagogical programme in the pre-schools.