Abstract Introduction “Sleep to forget and sleep to remember” model postulates that the content of emotional memory is strengthened during sleep while the arousal component is attenuated. Experimental sleep deprivation studies in healthy individuals have supported the model, but it is not known if sleep in individuals with insomnia, a condition of chronic poor sleep, provides the same effect on emotional memory. Methods Individuals reporting insomnia and good sleepers (n = 76 and n = 83 respectively; 83% female, mean age of 43.2 years) completed a picture-rating task to assess a) emotional valence ratings pre and post sleep and b) recognition accuracy post-sleep. In addition, an autobiographical memory task was completed during the day to assess a) the number of recalled memories in a 2-minute period for good and bad past events respectively, and b) emotional intensity ratings of the retrieved memories at the time the event occurred and how they feel now. Results Wilcoxon rank-sum test was used to assess group differences. Sleep diary variables on the experimental night showed that individuals with insomnia experienced a significantly more disrupted sleep than good sleepers (SOL: r = 0.537; WASO: r = 0.620; TST: r = 0.669). In the picture-rating task, there was no significant group difference for recognition accuracy (neutral stimuli: r = 0.016; negative stimuli: r = 0.018) or change in emotional valence pre-to-post sleep (neutral stimuli: r = 0.003; negative stimuli: r = 0.008). In the autobiographical memory task, individuals with insomnia remembered significantly fewer good days (r = 0.245) and rated their bad days at the time of its occurrence as significantly worse than good sleepers (r = 0.235). There was no significant group difference in the extent to which emotional intensity faded more for bad days than good days (r = 0.113). Conclusion We have shown that autobiographical memory is altered in insomnia which may have important influence on mental health. Our findings also suggest that overnight memory consolidation for negative stimuli is not affected in insomnia versus good sleepers. This may be a reflection of our one-night protocol; future work is needed across consecutive days. Support (if any) Dr-Mortimer-&-Theresa-Sackler-Foundation