Objectives: Evaluate clinical outcomes associated with implementing a specialist pneumonia intervention nursing (SPIN) service, to improve adherence with BTS guidelines for hospitalised community acquired pneumonia (CAP). Design: Retrospective cohort study, comparing periods before (2011-13) and after (2014-16) SPIN service implementation. Setting: Single NHS trust across two hospital sites in Leicester City, England Participants: 13,496 adult (aged ≥16) admissions to hospital with a primary diagnosis of CAP Interventions: The SPIN service was set up in 2013⁄2014 to provide clinical review of new CAP admissions; assurance of guidelines adherence; delivery of CAP clinical education and clinical follow up after discharge. Main outcome measures: The primary outcomes were proportions of CAP cases receiving antibiotic treatment within 4 hours of admission and change in crude in-hospital mortality rate. Secondary outcomes were adjusted mortality rate and length of stay (LOS). Results: The SPIN service reviewed 38% of CAP admissions in 2014-16. 82% of these admissions received antibiotic treatment in <4 hours (68.5% in the national audit). Compared with the pre-SPIN period, there was a significant reduction in both 30-day (OR=0.77 [0.70-0.85], p<0.0001) and in-hospital mortality (OR=0.66 [0.60-0.73], p<0.0001) after service implementation, with a review by the service having the largest independent 30-day mortality benefit (HR=0.60 [0.53-0.67], p<0.0001). There was no change in LOS (median 6 days). Conclusions: Implementation of a SPIN service improves adherence with BTS guidelines and achieves significant reductions in CAP associated mortality. This enhanced model of care is low cost, highly effective and readily adoptable in secondary care.