© 2015 Gazi Eye Foundation. All Rights Reserved.Purpose: To evaluate choroidal thickness in highly miyopic eyes and to correlate it with axial length, visual acuity, age and spherical equivalent. Materials and Methods: This study was composed of 21 eyes of 14 patients with high myopia (≥6 diopters or axial lenght ≥26 mm) and 20 eyes of 12 healthy volunteers. Choroidal thicknesses were manually measured by enhanced depth imaging optical coherence tomography from the posterior edge of the retinal pigment epithelium to the choroid-scleral junction. Statistical analysis was performed. Results: The mean age of high myopia group was 39.8±6.4 years (range, 28 to 51 years) and the mean axial length was 29.3±2.3 mm (range, 26 to 32 mm). The mean choroidal thickness was 104.2±21.6 µm and was correlated negatively with axial length, age, refractive error and visual acuity. Statsitical analysis suggested that choroidal thickness decreased by 3.9 µm for each milimeter of axial length and by 6.03 µm for each myopic dioptre. Conclusions: In highly myopic eyes choroidal thickness is thinner than emetropic eyes and undergoes further thinning with increasing with axial length, spherical equivalent and age. Our results supports that choroidal abnormalities may play a role in the pathogenesis of myopic degenerations.