Objective: Slow oscillations during sleep, which have their origin over prefrontal cortex (PFC) areas, support the consolidation of declarative memory.Children with attention-deficit/hyperactivity disorder (ADHD) display structural and functional deficits in PFC.Recently, we reported that in children with ADHD the consolidation of declarative memory during sleep is reduced due to diminished function of oscillatory PFC activity during delta sleep.We found signs that in ADHD particularly emotional memory consolidation during sleep was affected.The aim of the current study was to replicate these data in the light of healthy ontogenetic development.Methods: 16 children with ADHD (10;5 years), 16 healthy children (11;1 years) and 16 healthy adults (24;4 years) participated in this study.In a recognition task, pictures with negative emotional and neutral content were used in a within-subject study design.During the retrieval session, participants had to indicate whether or not they saw the presented picture already during the learning session.Two conditions were carried out: In the sleep condition, learning took place in the evening and retrieval was conducted in the morning after sleep;in a control condition with no sleep, learning took place in the morning and retrieval in the evening.Results: After sleep compared to wake condition, only healthy children displayed a gain in baseline-controlled emotional memory.Correlations between prefrontal slow oscillation power during delta sleep and sleep-associated gain in emotional memory were negative in children with ADHD, and differed from that in healthy children.Healthy adults did not show any correlation between slow oscillation power and emotional memory gain.Conclusions: Our data emphasise that the benefit of sleep in the consolidation of emotional memory underlies a decline from childhood to adultness.This suggests a vulnerable time window for emotional memory formation during healthy development, linked to PFC-generated slow oscillations.Based on PFC alterations, a reduced consolidation of emotional memory in ADHD children may contribute to their diminished ability to learn from negative emotional experiences.