Background: The aim of this study was to evaluate the course of tumor regression and visual impairment in choroidal melanomas treated by transpupillary thermotherapy (TTT) alone. Patients and Methods: In a prospective,non-randomized analysis 26 patients suffering from primary choroidal melanoma (posterior to the equator with base ≤ 12 and thickness ≤ 4.5 mm) were treated with the TTT standard protocol and followed for 33-45 months. Fluorescein and ICG angiographies were performed initially and after tumor regression clinically. Results: 22 tumors were significantly flattened after 1-3 TTT sessions. 4 tumors required additional therapy with ruthenium plaque. Visual acuity remained unchanged or improved in 11 eyes. In all eyes fluorescein and indocyanine green angiography revealed a sharp demarcation of the heat-treated area. Except for macular edema and gliosis in 6 eyes no vascular or retinal tissue damage was noticed outside the treatment zone. In the periphery of the treatment zone all eyes showed residual choriocapillaries remaining perfused. During follow-up 2 eyes revealed tumor regrowth at the posterior margin of the scar,which was successfully managed by TTT or a ruthenium plaque. 2 eyes developed late choroidal neovascularizations (CNV) in the heat-treated area. One patient died of liver metastases. Conclusions: Fluorescein and indocyanine green angiographic findings after TTT for small choroidal melanomas suggest that the tissue damage in the choroidal layer is less effective,which perhaps can lead to a higher rate of tumor regrowth. Development of choroidal neovascularization may be a sign of late heat induced side effects of TTT. Background: The aim of this study was to evaluate the course of tumor regression and visual impairment in choroidal melanomas treated by transpupillary thermotherapy (TTT) alone. Patients and Methods: In a prospective, non-randomized analysis 26 patients suffering from primary choroidal melanoma ( posterior to the equator with base ≤ 12 and thickness ≤ 4.5 mm) were treated with the TTT standard protocol and followed for 33-45 months. Fluorescein and ICG angiographies were performed initially and after tumor regression clinically. Results: 22 tumors were significantly flattened after 1-3 tumors were additionally unchanged with or without ruthenium plaque. Visual acuity unchanged unchanged or improved in 11 eyes. In all eyes fluorescein and indocyanine green angiography revealed a sharp demarcation of the heat-treated area. Except for macular edema and gliosis in 6 weeks no vascular or retinal tissue damage was noticed outside the treatment zone. In the periphery of the treatment zo during follow-up 2 eyes revealed tumor regrowth at the posterior margin of the scar, which was successfully managed by TTT or a ruthenium plaque. 2 eyes developed late choroidal neovascularizations (CNV) in the heat- treated area. One patient died of liver metastases. Conclusions: Fluorescein and indocyanine green angiographic findings after TTT for small choroidal melanomas suggest that the tissue damage in the choroidal layer is less effective, which perhaps can lead to a higher rate of tumor regrowth. Development of choroidal neovascularization may be a sign of late heat induced side effects of TTT.