ABASTRACT Background Nailfold capillaroscopy (NC) has been demonstrated to be an important tool in the diagnosis and treatment of patients with juvenile dermatomyositis (JDM) and systemic sclerosis. However, NC has been scarcely studied in adult patients with DM. Objectives Is to visualize capillary changes in DM/PM patients, trying to find a specific capillary pattern and its correlation if any- with disease activity in those patients. Methodology This is a cross sectional observational study included 20 patients (DM.Diagnosed on base of clinical, laboratory and histopathological findings. We excluded patients with hypertension or diabetes mellitus. The NFC performed using videocapillaroscope. A semiquantitative rating scale was used to score capillaroscopy changes. Myositis disease activity assessment tools were used to assess disease activity [Manual Muscle Testing (MMT), Myositis Disease Activity Assessment Visual Analogue Scales (MYOACT), Health Assessment Questionnaire (HAQ), physician’s VAS, patient’s VAS, skin scoring, serum muscle enzymes levels] Result The median age of our patients was 36 (S.D.12) Mean disease duration was 24months (S.D.19).The results presented mean value 3,8 (S.D.3,3) for muscle disease activity score,2(S.D.3) for skin score and 3,92 (S.D.3,09) for global disease activity .Enlarged capillaries was found in12 patients (100%), avascular areas in 10 patients (83.3%), capillaries hemorrhage in 8 patients (66,7%), and branched capillaries in 6 patients (50%).Sixteen patient (80%) had scleroderma like pattern. We found that disease activity positively correlate with branched capillaries(p = 0,04), muscle disease activity correlate positively with capillaries density score(p = 0,002) while hemorrhage correlate positively with skin score(p = 0,024). In our study major capillaroscopic abnormalities appeared to be virtually confined to patients with DM while patients with PM had only minor changes. No signifcant correlations between NFC and other demographic, clinical and laboratory parameters were observed. Conclusion NFC may provide helpful information about patients with PM/DM by: (a) contributing to the diagnosis and (b) correlating with disease activity parameters. Additional investigations with larger series of patients and prospective studies may be useful to reinforce our data.