Coronavirus disease 2019 (COVID-19) is a serious infectious disease with multisystem alteration including neurological complications. COVID-19 associated encephalitis is a potentially fatal viral infection of the brain. Diffusion-weighted images (DWI) are a useful evaluation modality of cytotoxic edema in patients with encephalitis. We report on the reversible DWI change in a patient with COVID-19 associated encephalitis, who had diffused cytotoxic edema in the affected temporal lobe and accompanied status epilepticus. Sequential imaging showed that the cytotoxic edema in DWI confirmed recovery to normal after 12 days in the presence of cortical edema in fluid-attenuated inversion recovery image after aggressive neurocritical management. Thus, prompt, proper management is indispensable during the acute period and DWI may be a valuable tool for reflecting the clinical course of COVID-19 associated encephalitis.