Active boosting of the antitumour immune response of patients with solid malignancies has been tested in a large number of trials. Isolated complete clinical responses have been reported, however, they have not been replicated in subsequent studies. We recently reported objective clinical responses to a dendritic cell/irradiated autologous tumour cell 'vaccine' in patients with distant metastatic (stage IV) melanoma. Here we describe our experience in a second cohort of patients with stage IV melanoma, using this dendritic cell-based immunotherapy in a cryopreserved format. Of 46 patients enrolled into the study, three had complete remission of all detectable disease, and a further three had partial clinical responses. These data confirm that dendritic cell-based immunotherapy has potential as a therapy in a limited number of patients with stage IV melanoma. To our knowledge, this is the first demonstration that cryopreserved dendritic cells can elicit complete clinical responses in patients with advanced cancer. Our observations support randomized controlled trials to validate the findings.