Three disease-modifying drugs (Nusinersen, Risdiplam and Onasemnogene abeparvovec) have been approved for SMA type I. Onasemnogene abeparvovec (GRT) can be administered in naïve patients or patients who are already being treated with Nusinersen or Risdiplam. Safety data on GRT in naïve patients or previously treated Nusinersen have been extensively described whereas any case of switch therapy from Risdiplam to GRT has been reported yet. We report on a SMA type I patient treated with Risdiplam by 2 months and switched to GRT at 5 months. She manifested the more common and awaited side effects that resolved in 3 months. The follow-up after 9 months from GRT infusion showed normal blood count, renal and cardiac function. She had great improvement in motor outcome, and no respiratory and bulbar problems as well as normal neurocognitive profile. This case suggests that the GRT may be safe also in patients previously treated with Risdiplam.