Introduction: The use of high resolution ultrasonography (US) became a very important tool in nail assessment. This study evaluated nails clinical and ultrasound measurements in the psoriatic arthritis (PsA) patients and control groups. Methods: A cross sectional study was performed and 44 patients with PsA, 10 health individuals and 6 hand osteoarthritis patients (OA) were selected. PsA patients were included when filling the CASPAR criteria. Results: spectral Doppler (sD) was analyzed in 208 nail beds. Nail plates appearance on gray scale (GS) showed loss of the normal three-layered appearance in 89 nails (45.9%). Power Doppler (PD) signal was detected in 189 nail beds (92.2%), showing inflammatory activity in most of the patients and nails examined. Resistance index (RI) measured was significantly lower in PsA patients as compared with controls group in both longitudinal and transverse planes (p<0.001). The nail enthesitis was observed when RI values below 0.4, characterizing 100% sensitivity and 96% specificity (p<0.01). Conclusions: Nail US measurements presented statistical significance in PsA patients, in studies future could show many inflammatory situations, as treatment assessment.