Aim — to specify indications for brachytherapy (BT) in large choroidal melanoma (CM) so that tumor size and vital prognosis were considered. Material and methods. We retrospectively analyzed data from 161 CM patients who were treated with BT and followed-up at either the Ophthalmological Clinical Hospital or some other Moscow medical facility and also registered by the City Cancer Registry. Results. Patient age at the time of starting the treatment lied within the range of 17 to 84 years and averaged 56.89±1.93 years. During the follow-up period (12—275 months, 95.65±8.4 months on average) hematogenous metastases were found in 23 (14.29%) patients. Liver involvement was diagnosed in 8 patients within the average of 23.13 months after treatment. Their average survival time was 11 months. A total of 142 patients were followed up for more than 36 months (104.87 months on average). Of them, 15 patients were diagnosed with metastatic CM within 37—167 months after BT (80.27 months on average). Despite metastatic disease they generally survived 2.8 time longer than the aforementioned patients (30.8 months). The cases were then divided into 3 groups according to J. Shields classification of CM. Small melanoma patients did not develop metastases within 99.96±12.47 months of follow-up. In medium melanomas, as many as 13.35% of cases were metastatic (with the average survival time of 20.66 months); in large melanomas — 19.51% (with the average survival time of 13.5 months). Conclusion. Treatment modality and follow-up periods being the same (7—8 years after BT), larger choroidal melanomas has been shown to be associated with higher risk of hematogenous metastases. For local treatment to be successive, the maximal diameter of the tumor should not exceed 10 mm. Every fifth patient of those with CM larger than 15 mm is likely to develop hematogenous metastases. The results obtained indicate the necessity of decreasing the size thresholds for choroidal melanomas, small and medium in the first place.