To study the early anatomic choroidal alterations in eyes with chronic central serous chorioretinopathy (CSCR) undergoing photodynamic therapy (PDT). Multicenter retrospective cohort study. A total of 77 patients and 81 eyes with chronic CSCR treated with PDT and 64 untreated fellow eyes were evaluated. Central macular thickness (CMT) and choroidal features including subfoveal choroidal thickness (SFCT), total choroidal area (TCA), luminal choroidal area (LCA), and stromal choroidal area (SCA) were analyzed. Choroidal vascularity index (CVI) was calculated in all study eyes at baseline and at 1- and 3-months post-PDT. In eyes receiving PDT, Snellen visual acuity (VA) significantly improved at months 1 and 3 (P < .001). CMT and SFCT showed a significant reduction from baseline at months 1 and 3 (P < .001), whereas TCA and LCA showed a significant decrease only at the 1-month follow-up visit. Baseline mean TCA and LCA were 2.30 ± 1.41 mm2 and 1.23 ± 0.73 mm2, respectively, and decreased to 2.07 ± 1.21 mm2 and 1.08 ± 0.63 mm2 at the 1-month follow-up visit, respectively (P = .01). No significant changes were recorded for SCA and CVI. In the fellow eye group, VA, CMT, and all choroidal parameters showed no differences between baseline and any follow-up visits (all P > .05). After PDT for chronic CSCR we observed sustained reductions in CMT and SFCT, while reductions in TCA and LCA were only noted at the 1-month follow-up interval. These choroidal parameters may provide additional quantitative biomarkers to evaluate the anatomic response to therapy but await further prospective validation.