PURPOSE: To investigate the morphologic and functional outcomes of nanosecond subthreshold (ST) laser treatment for patients with chronic central serous chorioretinopathy (CSC). METHODS: In this prospective study, 44 patients were treated with the ST nanosecond laser with a follow-up period of 12 months. All target variables were measured at 1, 3, 6 and 12 months after the first laser treatment. RESULTS: This study showed a significant improvement in macular sensitivity (MS), a significant reduction in central macular thickness (CMT) as well as a significant reduction in subretinal fluid height (SRF) after 3 months of treatment. The subfoveal choroidal thickness (SFCT) was significantly reduced after 12 months of treatment. However, the best-corrected visual acuity (BCVA) (logMAR) did not change significantly at any time during the study. A high proportion of patients (85%) showed complete resolution of SRF after 12 months, indicating a positive response to treatment in the majority of our patients. CONCLUSION: This study showed statistically significant functional improvement in MS as well as significant anatomical reduction in CMT, SFCT and SRF height in CSC patients treated with ST nanosecond laser therapy. Patients with higher SRF at baseline required repeated laser treatments to achieve complete resolution of the SRF.