This population‑based study examined capillary leak syndrome (CLS) among children with multisystem inflammatory syndrome in children (MIS‑C) in Skåne, Sweden. Among 31 MIS‑C patients aged 0–18 years, CLS occurred in 45% and was present in all six patients requiring intensive care. CLS was associated with reduced cardiac function, higher C‑reactive protein and NT‑proBNP levels and lower platelet counts. Patients with CLS received more intensive immunosuppression. CLS was a common complication and was linked to a more severe disease course.