Background We aimed to determine the association between seizure termination and side effects of isoflurane for the treatment of refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE) in neurointensive care units (neuro-ICUs). Methods This was a multicenter retrospective study of patients with RSE/SRSE treated with isoflurane for status epilepticus termination admitted to the neuro-ICUs of nine German university centers during 2011–2018. Results We identified 45 patients who received isoflurane for the treatment of RSE/SRSE. During isoflurane treatment, electroencephalograms showed no epileptiform discharges in 33 of 41 (80%) patients, and burst suppression pattern was achieved in 29 of 41 patients (71%). RSE/SRSE was finally terminated after treatment with isoflurane in 23 of 45 patients (51%) for the entire group and in 13 of 45 patients (29%) without additional therapy. Lengths of stay in the hospital and in the neuro-ICU were significantly extended in cases of ongoing status epilepticus under isoflurane treatment (p = 0.01 for length of stay in the hospital, p = 0.049 for length in the neuro-ICU). During isoflurane treatment, side effects were reported in 40 of 45 patients (89%) and mainly included hypotension (n = 40, 89%) and/or infection (n = 20, 44%). Whether side effects occurred did not affect the outcome at discharge. Of 22 patients with follow-up magnetic resonance imaging, 2 patients (9%) showed progressive magnetic resonance imaging alterations that were considered to be potentially associated with RSE/SRSE itself or with isoflurane therapy. Conclusions Isoflurane was associated with a good effect in stopping RSE/SRSE. Nevertheless, establishing remission remained difficult. Side effects were common but without effect on the outcome at discharge.