Purpose We investigated whether duration of untreated psychosis (DUP) prior to first presentation was associated with cognitive function in first episode psychosis (FEP) subjects. We predicted that longer DUP would be associated with greater neurocognitive impairment. Method 180 subjects with schizophrenia (and 93 subjects with Other Psychoses) performed a neurocognitive battery assessing IQ, verbal learning, working memory, visual learning and speed of processing. DUP was defined as the number of days between first onset of psychotic symptoms and first contact with psychiatric services. Results Longer DUP was associated with impaired performance in verbal IQ (p =0.04), verbal learning (p =0.02), and verbal working memory (p =0.04) in FEP subjects with schizophrenia. These associations remained significant for verbal IQ when scores were corrected for age, gender, educational level and ethnicity. Conclusions Longer DUP is associated with poorer neurocognitive ability in schizophrenia subjects at time of first presentation. Since this was a cross-sectional study we can not tell whether longer DUP was a cause or a consequence of the poorer performance.