This study investigates the indoor air quality and thermal comfort within six Latvian daycare centres (old, renovated and new-built). Measurements of carbon dioxide, air temperature and relative humidity have been carried out and the daycare centre characteristics data have been collected. Carbon dioxide concentrations exceeded 1000 ppm in 75% of the daycare centres studied, with the highest concentration (1356 ppm) measured in a renovated facility. In all facilities the temperature is kept above 20°C and the average relative humidity is 40 ± 5%, thus creating a comfortable thermal environment for children