The results of bone puncture (P) or aspiration biopsy (AB) in a series of 82 patients with skeletal metastases are reported. In 71 patients, AB of the posterior iliac crest was performed systematically, irrespective of the site of the bone lesion and without aiming at a suspicious area. In 11 patients, P or AB were guided by televised fluoroscopy towards an image of bone metastasis. With either method, a diagnosis of metastasis was made in 42/82 patients, i.e. 50%. With the first method, positive results were obtained in 43.7% of the cases; the figure rose to 54% in cases with known primary cancer and abnormal X-ray image and dropped to 36% in cases with abnormal image and no history of cancer, and to 9 p. 100 in cases with normal X-ray films. In all 11 patients had fluoroscopy-guided P or AB, histological examination of the specimens was positive for metastasis.