We performed survival studies on 136 patients with uveal malignant melanoma who were examined with ultrasonic tissue characterization before treatment with cobalt-60 brachytherapy (74 patients) or enucleation (62 patients). Mean follow-up time was 58.7 months for the brachytherapy group and 59.0 months for the enucleated group. The maximal follow-up time was nearly ten years. Univariate survival analysis showed that patients with small tumors (less than 250 mm3, 49 patients) had a higher five-year survival when treated with brachytherapy than when treated with enucleation. No patients in this study with tumor volumes greater than 1,500 mm3 (13 patients) were treated with brachytherapy. For tumors of intermediate size (74 patients), survival analysis did not indicate appreciable differences between the treatment options. However, multivariate models including two ultrasonic tissue characterization variables, scatterer size and concentration, showed appreciable intergroup differences in the dependence of survival on these factors. Results suggest that tissue properties detectable with ultrasonic techniques are related to differences in patient survival and may be used for treatment planning for tumors of intermediate size.