We studied selective in vivo and in vitro immunologic factors of 25 patients with choroidal malignant melanoma. Immune profile factors did not show consistent differences between patients with melanoma and an age-matched control population. The studies were also non-contributory in delineating variations in immunocompetence with respect to melanoma cell types. Serial immune profiles failed to identify a change when clinical evidence of metastasis developed. When tested as a group, patients with melanoma in whom metastatic disease developed during the study showed significant depression of initial mitogen-induced lymphocyte blastogenesis. This depression was noted in advance of clinically recognized metastatic disease. This group had a wide range of responses that overlapped those of control patients, thus making the usefulness of these testing factors questionable for individual prognosis or for clinical monitoring.