Recent research suggests that the cortisol awakening response (CAR) is linked to cognitive functions depending on hippocampal and frontal cortex circuits and may possibly be modulated by prospective memory (PM). However, the link between the CAR and PM abilities has not been investigated so far. Addressing this open issue, we report data from 97 children aged 37–87 months. Salivary cortisol levels were assessed 0 and 30min post-awakening over three study days. Thereby a valid CAR measurement was ensured by using objective measures of awakening and sampling times. A game-like task served as behavioral measure of PM performance. Bayesian analysis revealed a positive association between children's PM performance and the CAR, with better PM performance being related to a greater CAR. This association persisted after controlling for age. Overall, the current finding supports the prediction that PM functioning may be linked to the CAR, possibly as both the CAR and PM rely on a common neurophysiological basis.