PurposeInsomnia-related affective functional disorder may negatively affect social cognition such as empathy, altruism, and attitude toward providing care. No previous studies have ever investigated the mediating role of attention deficit in the relationship between insomnia and social cognition.MethodsA cross-sectional survey was carried out among 664 nurses (Mage= 33.03 years; SD ± 6.93 years) from December 2020 to September 2021. They completed the Scale of Attitude towards the Patient (SAtP), the Athens Insomnia Scale (AIS), a single-item numeric rating scale assessing the increasing severity of attention complaints, and questions relating to socio-demographic information. The analysis was carried out by examining the mediating role of attention deficit in the relationship between insomnia and social cognition.ResultsThe prevalence of insomnia symptoms was high (52% insomnia using the AIS). Insomnia was significantly correlated with attention problems (b= 0.18, standard error (SE) = 0.02,p< 0.001). Attention problems were significantly negatively correlated with nurses’ attitudes towards patients (b = −0.56, SE = 0.08,p< 0.001), respect for autonomy (b = −0.18, SE = 0.03,p< 0.001), holism (b = −0.14, SE = 0.03,p< 0.001), empathy (b = −0.15, SE = 0.03,p< 0.001), and altruism (b = −0.10, SE = 0.02,p< 0.001). Attention problems indirectly mediated the effect of insomnia on attitudes toward patients (99% CI = −0.10 [−0.16 to −0.05]), respect for autonomy (99% CI = −0.03 [−0.05 to −0.02]), holism (99% CI = −0.02 [−0.04 to −0.01]) empathy (99% CI = −0.03 [−0.04 to −0.01]), and altruism (99% CI = −0.02 [−0.03 to −0.01]).ConclusionNurses with insomnia-related attention problems are likely to have poor explicit social cognition such as attitude toward patients, altruism, empathy, respect for autonomy, and holism.