Background: A shorter duration of untreated psychosis (DUP) is associated with better outcomes following first-episode psychosis (FEP; Power et al., 2007; Birchwood et al., 2013; McGorry et al., 2008). However, the evidence on social and clinical factors that may predict to DUP is inconsistent. Aims: To investigate the association between DUP and social and clinical factors. Methods: A retrospective incidence study design was employed, using the Biomedical Research Centre (BRC) clinical record interactive search (CRIS) system. In brief, CRIS is a regional case register based in South London containing a large data set of anonymous clinical data of over 250 000 patient records derived from the South London and Maudsley NHS Foundation Trust (SLaM) electronic health record system. All patients presenting to SLaM adult mental health services for the first time with a psychotic disorder between May 2010 and April 2012 and in the catchment area served by SLaM were screened for inclusion. Data relating to DUP, sociodemographic characteristics, mode of contact, and source of referral were collated from clinical records. Individuals were included as cases if they were: resident in the London boroughs of Lambeth or Southwark (served by SLaM); aged 18–64 years (inclusive), experienced psychotic symptoms of at least one day duration, and were making their first contact for psychosis with mental health services. Results: A total of 558 individuals with first-episode psychosis were identified. Individuals who were unemployed (68.5%) experienced longer DUP (median = 119; interquartile range= 28–492) compared to people who were employed (19.6%; median =45; interquartile range= 6–426, P < .001). Living alone (29.7%) was also associated with longer DUP (median = 116; interquartile range = 30–531) compared to living with family/relative (median = 90; interquartile range = 14–370, P = .04). Further, an insidious mode of onset of psychosis (37.5%) was associated with longer DUP (median = 608; interquartile range = 360–1918) compared to acute onset (20.7%; median = 4; interquartile range = 2–6.5, P < .001). Similarly, individuals accessing care via accident and emergency departments (A&E 38.9%) experienced shorter DUP (median = 41; interquartile range = 6–295) compared with those referred by their general practitioner (GP 35.1%; Median=184.5; interquartile range = 46.5–821.5, P < .001). Conclusion: Findings from this sample of FEP patients suggest that indicators of social isolation were associated with DUP. Clinically, pathways into care were also strongly associated with DUP prior to help seeking. Our results are consistent with previous findings.