BACKGROUND: Schizophrenia and bipolar disorder are associated with significant deficits in neurocognition and social cognition. Unlike the studies in chronic stages of these disorders, very limited information is available regarding neurocognitive and social-cognitive impairment before the onset of bipolar disorder. Our main aim was to investigate the differences in neurocognition and social cognition between individuals at ultra-high risk for psychosis (UHR-P) and bipolar disorder (UHR-BD). METHODS: This study included 152 help-seeking individuals identified as UHR-P (n = 78) and UHR-BD (n = 74), who were compared with a healthy control group (n = 43). A comprehensive neuropsychological battery was administered to all participants. RESULTS: UHR-P was associated with widespread deficits in all neurocognitive and social-cognitive domains. Effect sizes (Cohen's d) of these deficits ranged from -0.57 to -1.34. UHR-BD was associated with significant deficits in processing speed, executive functions, sustained attention and social cognition (d = -0.48 to-0.70, p < 0.05). UHR-P performed significantly worse than UHR-BD in social cognition, processing speed, verbal memory and executive function domains (d = -0.39 to-0.64, p < 0.05). Negative symptoms were associated with impaired social cognition in the UHR-P group and verbal memory deficits in the UHR-BD group. Cognitive impairment was associated with functional impairment in both groups. CONCLUSIONS: While UHR-P is associated with more widespread cognitive impairment, deficits in processing speed, executive functions, sustained attention and social cognition might be common features of both UHR groups. In early intervention services, cognition should be considered as a target for assessment and intervention not only for individuals at high risk for psychosis but also for bipolar disorder.