Symptomatic calcifications of the rotator cuff tendons is well-known pathologic condition. However, pathologic calcifications may involve other structures of the locomotor system as well. We report about five patients (age 52-66 years) with a painful calcification at the proximal part of the medial collateral ligament of the knee joint. All five patients presented with load-dependent pain pretending meniscus symptoms, but manual valgus stress provoked severe pain at the medial side of the knee. Conventional X-ray examination showed a dense rounded deposit at the proximal part of the medial collateral ligament. Initially all patients were treated conservatively by needling and infiltration with a local anaesthetic. Open resection of the deposit was performed in four patients after unsuccessful conservative treatment. Postoperatively all patients were immediately free of pain. After a mean follow-up of 6 years (patient 1-4) (range=2.5-9.5 years), all patients were still free of pain. Histological evaluation of biopsies obtained during surgery showed nodular deposition of calcium at the collagen fibres, vascular proliferations and inflammative changes. Soft tissue calcifications have to be considered as a rare differential diagnosis in patients presenting with medial knee joint pain. Open resection reduces symptoms immediately. The histological changes seen were comparable to that reported about pathological tendon calcifications of the shoulder. Therefore, both conditions might be of the same aetiology.