Molecular imaging (SPECT/PET) and CT/MRI techniques have been used for the assessment of renal and prostate cancer for decades, principally in assessing renal tract function, cardiac reserve prior to and during therapy, and identifying bony metastatic disease. More recently, the use of PET tracers, new MRI techniques, and radiolabelled monoclonal antibodies, has emerged as important techniques for the staging of renal and prostate cancers, assessing treatment response, and molecularly characterising gene and receptor expression in-vivo. FDG PET has been used clinically to detect primary and metastatic renal cancer, and guide treatment. More recently, ¹²⁴I-cG250 (Reductane®) has enabled the accurate identification of clear cell renal carcinoma, and a recently completed Phase III trial has shown a sensitivity and specificity of 86% and 87% respectively. Imaging of hypoxia and proliferation in renal cancer with PET tracers has also been evaluated. PET has been used extensively to evaluate locally advanced and metastatic prostate cancer, with FDG PET useful particularly for detection of metastatic disease. ¹¹C-choline and ¹⁸F-choline PET has been shown to be more accurate in detecting prostate cancer than FDG PET, and ¹⁸F-FDHT PET can identify patients who respond to anti-androgen therapy. We have shown that choline PET can assist with presurgical staging, and in particular guide radiotherapy treatment planning. Sophisticated MRI techniques have also been developed that allow more accurate identification of primary and metastatic disease, and monitoring response to treatment. Data on the latest advances in GU imaging will be presented.