Bone metastases are common by prostate and renal carcinomas but prostate carcinomas are predominantly osteoblastic metastases and renal carcinomas often osteolytic. Apart from bone scintigraphy and conventional X-ray imaging, computed tomography (CT), magnetic resonance tomography (MRT) and positron emission tomography (PET) can also be used for primary diagnosis. X-rays and CT are less sensitive but better for evaluating the stability of metastases. Primary diagnosis of prostate carcinomas should encompass selective bone imaging and skeletal scintigraphy is also recommended. Local recurrences or lymph node metastases can be detected using PET with (11)C-choline. MRT is the method with higher sensitivity and specificity but for whole body scans is, at present, very time-consuming and, therefore, impractical and cost-intensive. However, for selective, non-invasive valency evaluation of suspect metastases, it is considered the gold standard for the tumor entities prostate and renal carcinomas where the results of FDG PET are consistently negative.