We report the case of a 43-year-old female patient who was admitted to the Cardiology Department from the Rheumatology Clinic where she was being treated for multi-organ serositis, fatigue and mild dyspnoea on exertion. The patient had a known medical history of systemic lupus erythematosus (SLE). Following extensive evaluation with blood tests for immunological and viral culprits, cardiac ultrasound, chest and abdominal computed tomography (CT) and heart magnetic resonance imaging (MRI), the diagnosis of effusive constrictive pericarditis secondary to her SLE was made. Treatment with β-blockers, diuretics and corticosteroids was given with excellent results, and one year post discharge the patient remains asymptomatic. Systemic lupus erythematosus patients often manifest cardiac complications such as pericarditis. The practising physician should always bear in mind this possibility when treating such patients.