Ultrasound-guided needle biopsy is a safe and efficient diagnostic method increasingly used in the initial approach to superficial and deep musculoskeletal tumours. However, so far no general consensus has been reached regarding its reliability. During a 6-year period (1999-2004), biopsies were taken from 188 patients (100 females, 88 males; age average 55.8 years) with musculoskeletal tumours under ultrasound guidance using 18G BioPince or 14G ProMag 2.2 true-cut type needles. Cytological (imprints and cytocentrifugates) and histological material was obtained for diagnosis in every case. The lower extremity (59 cases) and the abdominal wall (29 cases) were the most commonly affected sites. Benign/reactive tumours (77 cases), metastatic epithelial malignancies (40 cases), and sarcomas (36 cases) were most frequently diagnosed. In 180 (95.75%) cases, core needle results were concordant with the definitive diagnosis (97 true positives and 83 true negatives). Relevant diagnostic discordance was seen in 8 (4.25%) cases (8 false negatives and 0 false positives). Sensitivity, specificity and positive and negative predictive values were 92%, 100%, 100%, and 91%, respectively. Ultrasound-guided core biopsy is thus a useful method in the initial approach to musculoskeletal tumours that allows correct patient management in the vast majority of cases.