Patients with immune-mediated rheumatic disease-related calcinosis comprise a subgroup at risk of encountering a more severe clinical outcome. Early assessment is pivotal for preventing overall disease progression, as calcinosis is commonly overlooked until several years into the disease and is considered as a ‘non-lethal’ manifestation. This single-center retrospective study explored the prevalence, clinical associations, and impact on survival of subcutaneous calcinosis in 86 patients with immune-mediated rheumatic diseases (IMRD). Calcinosis predominantly appeared in individuals with longstanding disease, particularly systemic sclerosis (SSc), constituting 74% of cases. Smaller calcinosis lesions (≤1 cm) were associated with interstitial lung disease, musculoskeletal involvement, and digital ulcerations, while larger lesions (≥4 cm) were associated with malignancy, severe peripheral artery disease, and systemic arterial hypertension. The SSc calcinosis subgroup exhibited a higher mean adjusted European Scleroderma Study Group Activity Index score than those without. However, survival rates did not significantly differ between the two groups. Diltiazem was the most commonly used treatment, and while bisphosphonates reduced complications related to calcinosis, complete resolution was not achieved. The findings underscore current limitations in diagnosing, monitoring, and treating calcinosis, emphasizing the need for further research and improved therapeutic strategies to improve patient care and outcomes.