Psoriatic arthritis (PsA) is an infl ammatory disease with potential involvement of both peripheral and axial skeleton which has variable clinical course and several degrees of severity. Ultrasound (US) is a rapidly evolving technique that helps to actually determine the anatomical structure involved in the infl ammatory process and is one of the imaging method recommended to assess synovitis at any joint and has the potential to be used not only to detect joint synovitis, but also to assess surrounding soft tissues in order to determine the presence of tenosynovitis, dactylitis and/or enthesitis. Doppler modalities are currently considered an integral part of the global US assessment of the rheumatic patient. This is mainly due to their capability to detect pathological fl ow within musculoskeletal soft tissues, thereby demonstrating the presence of local active infl ammation. US has several advantages over other imaging techniques: it is patientfriendly, safe, noninvasive, less expensive, and permits multiple target assessment in real time without the need for external referral. Available data demonstrate that US can be regarded as a feasible and effective imaging technique that can allow early recognition of anatomical changes, infl ammatory subclinical fi ndings, differential diagnosis, careful guidance for aspiration and/or local treatment, and short-term therapy monitoring at joint, tendon, enthesis, nail, and skin levels. Further research is required into implications of the disparity between US and clinical fi ndings, to really determine the signifi cance of subclinical fi ndings to predict structural damage, relapse and progression of the disease. There is also a need to validate PsA specifi c composite multi-target US scoring systems. This chapter summarize the main potential applications of US in cutaneous psoriasis and PsA patients.