Introduction: Characteristic of juvenile dermatomyositis, calcinosis cutis remains rare on adults and the diffuse form (cacilnosis cutis universalis) is exceptional. We report two observations of cacilnosis cutis universalis in adult dermatomyositis. Observations: Two women aged 29 and 24 years respectively, diagnosed with primitive dermatomyositis according to the criteria of Tanimoto and al. and the European neuromuscular centre, developed after 2 years and 16 months of the beginning of the disease a calcinosis cutis universalis confirmed by radiological explorations and biopsy. They were treated by Cochicine and Diltiazem with relative stabilization. Conclusion: As rare as it is, calcinosis cutis universalis is an entity which deserves to be well-known during adult dermatomyositis in order to ensure an adequate and fast treatment especially with the possible risk, recently proven, of malignancy arising from this dystrophic calcifications.