This study examined several early childhood education and care (ECEC) factors and their relation to children's salivary cortisol slope and hair cortisol concentration (HCC). The study is part of the cross-sectional DAGIS study, conducted in 2015-2016, examining 66 preschools and 677 children aged 3-6 years in Finland. Two saliva samples from one childcare day and a hair sample were collected from the children. Educators' education level, perceived stress, and occupational well-being factors, group size, child-adult ratio, and amount of childcare per week were assessed by questionnaires filled in by educators and guardians. Higher educators' education level was associated with a higher likelihood of children having a declining salivary cortisol slope. Educators with higher perceived stress were associated with a lower likelihood of children having a declining cortisol slope, but the result was attenuated in the adjusted model. Child-adult ratio was negatively associated with HCC. The results indicate that educators' higher education level and possibly lower stress associate with a favourable cortisol profile in children, suggesting less stress. These factors should receive attention when considering children's stress at childcare.