AIM: This paper describes findings from a study that evaluated the implementation and impact of case management for long-term conditions (CMLTC) in 10 primary care trusts (PCTs). BACKGROUND: Patients who have long-term conditions and complex health and social needs may require case management to deliver and coordinate their care from a range of agencies. METHODS: A cross-sectional postal survey of managers with lead responsibility for CMLTC in each PCT is adopted to describe the implementation of services. A retrospective cohort analysis of longitudinal routinely collected admission data for patients enrolled within the CMLTC service (nine months before and nine months after the entry; n = 867) is used to measure their impact. FINDINGS: The organisation of case management varied between PCTs in some aspects despite a high level of coordination across the geographical area. Mean emergency admissions and associated length of stay (LOS) for patients reduced significantly in the nine months after the service entry. There were a number of fairly robust positive and negative influences on these outcome measures in the regression analysis. Most patients with a history of emergency admissions experienced a marked improvement over time. However, most of those without any or with few admissions experienced an increase in admissions and corresponding LOS. Furthermore, a proportion of frequent service users with particular diagnoses also experienced an increase or remained at a high level. A very modest effect was shown with regard to the features of case management arrangements. For each day spent in hospital before service entry, patients are predicted to experience a reduction of nearly one day after. The main contributor explaining increases in LOS for emergency admissions was the number of primary and secondary diagnoses. Each added diagnosis is associated with a 2.4-day increase in LOS, everything else being equal.