Eteplirsen is an antisense oligonucleotide used in the treatment of Duchenne muscular dystrophy (DMD). The safety of eteplirsen use in individuals with rare comorbid conditions is not known. We present the case of a 4-year-old boy with a DMD exon deletion amenable to treatment with eteplirsen and comorbid sickle cell anemia. He has received eteplirsen treatment for 3 years with no clear adverse effects, including no increase in sickle cell crises.