Summary. Recurrent haemarthrosis is the final cause of haemophilic arthrosic disease in haemophilia patients. Therefore, it is essential to diagnose it early, both clinically and by imaging. In addition, haemophilia patients experience chronic synovitis, joint degeneration, muscle haematoma and pseudotumours. The objective of this article is to highlight the value of ultrasounds in the diagnosis and control of the evolution of musculo-skeletal problems in haemophilia patients. To this end, we have performed a literature search in the PubMed, Web of Science® (WOS) and SciVerse bases, using the following keywords: hemophilia or haemophilia and ultrasonography (US), ultrasound, echography and sonography. The search was limited to studies published in English between the years 1991 and 2011, finding a total of 221 references. After reviewing the title or abstract for evidence of the use of US for the diagnosis of musculo-skeletal lesions in haemophilia, we selected 24 of these references. We added data collected from our experience to the most important data found in the references. Our main conclusion is that US is highly valuable for the diagnosis of musculo-skeletal diseases in haemophilia. It is a fast, effective, safe, available, comparative, real-time technique that can help us confirm the clinical examination. It is particularly important in acute haemarthrosis, as it can be used to objectively identify the presence of blood in the joints, measure its size, pinpoint its location, assess its evolution and confirm its complete disappearance.