Background: Cyclosporine (CS) is a first-line immunosuppressive agent used to manage moderate to severe atopic dermatitis (AD). To date, the risk of developing hypertension associated with the long-term use of low-dose CS in AD patients is understudied. Objective: To determine the cumulative dose-dependent effect of CS on the risk of developing hypertension in patients with AD. Methods: A nationwide population-based retrospective cohort with 1,844,009 AD patients was built from the Korean National Health Insurance System database from 2005 to 2009.A Cox proportional-hazard regression analysis was performed according to patients’ CS treatment history adjusted for potential confounders. Results: Current use of CS was associated with an increased risk of developing hypertension (adjusted hazard ratio, 4.442; 95% confidence interval, 3.761–5.247). Among the current CS users, a higher cumulative dose of CS (≥39,725 mg) or longer cumulative use of CS (≥182 days), was significantly associated with an increased risk of developing hypertension. Conclusion The incidence of CS-associated hypertension is very low when using low-dose treatment regimens for AD. However, the current use or a high cumulative dose of CS for treating patients with AD increases the risk of developing hypertension. Precaution is needed when prescribing CS for long-term treatment of AD.