Cyclosporine is a systemic therapy used for control of severe atopic dermatitis (AD) in children. Although traditionally recommended at a dose of 5 mg/kg/day for 6 months, a longer duration of treatment may be necessary to bring a child with active and severe disease into remission. There are few data on the short- and long-term effectiveness of longer courses of therapy. This was a retrospective chart review of children treated with cyclosporine at a Canadian hospital-affiliated clinic between 2000 and 2013. Fifteen patients with adequate follow-up were identified. Twelve (80%) were male and the mean age at initiation of cyclosporine was 11.2 ± 3.4 years. The mean duration of cyclosporine therapy was 10.9 ± 2.7 months (range 7–15 months) at a starting dose of 2.8 ± 0.6 mg/kg/day. Of 12 patients (80%) who responded to cyclosporine, 5 patients (42%) had relapsed at a follow-up of 22.7 ± 15.0 months. The duration of therapy was longer in patients who did not relapse (17.7 ± 10.7 months) than in those who did (10.2 ± 2.7 months) (p = 0.06). Adverse events led to discontinuation in three patients (20%) and included infection-related complications in two patients and reversible renal toxicity in one. These results suggest that a longer duration of low-dose cyclosporine may help decrease the risk of relapse in patients with severe AD who are resistant to topical therapies.