AIM: To study the changes in choroidal thickness in central serous chorioretinopathy (CSCR) over a 3mo follow-up using spectral domain optical coherence tomography (SD-OCT). METHODS: This prospective study included 60 eyes, both eyes of 20 patients (mean age: 33.65±5.24y) with classic acute unilateral central serous chorioretinopathy and normal fellow eye and 20 eyes as healthy controls. Fluorescein angiography and OCT were done. The subfoveal choroidal thickness (SFCT), central macular thickness (CMT), 1000 μm temporal and nasal to the centre of the fovea and the subretinal fluid were measured. RESULTS: There was a statistically significant difference in SFCT among the three groups at the three different locations. SFCT in eyes with CSCR (372.40±34.39 μm) was significantly greater than that in each of the unaffected fellow eyes (302.10±8.9 μm) and control eyes (279.80±14.49 μm) at the base line and after 3mo follow-up. The mean CMT in CSCR was 317±141.86 μm, with a statistically significant positive correlation between SFCT and CMT. CONCLUSION: The increase in the choroidal thickness at different locations as well as hyper-dilated and hyper-permeable vessels known as “pachychoroid” seems to play an important role in a broad spectrum of diseases that includes central serous chorioretinopathy.