In the last years musculoskeletal ultrasound (US) has become a very useful imaging tool for the evaluation of rheumatic patients and a natural extension of the clinical examination of the ankle and foot. Musculoskeletal US allows the evaluation of the symptomatic and asymptomatic ankle and foot with a detailed analysis of a wide range of elementary lesions at the level of different anatomical structures and their distribution in early or long standing disease. In inflammatory pathology, it helps in the assessment of the disease activity and severity at the joint, tendon or entheseal level and in the detection of subclinical pathological features in early disease or residual activity after therapy. Moreover, US guided procedures allow accurate diagnostic and therapeutic interventions. It is a valuable imaging method that can be also used in the follow up of the treated patients (systemic and/ or local therapies or surgical procedures), being a patient friendly, non-invasive, and quick to perform method. The aim of this paper is to review the US technique of scanning and the indications of US in the analysis of the ankle and foot in rheumatic diseases.