A 66-year-old woman presented with new onset generalised tonic-clonic seizures following her first dose of chemotherapy comprising Rituximab, Cyclophosphamide, Hydroxydaunorubicin, Oncovin and Prednisolone (R-CHOP) 10 days earlier for non-Hodgkin’s lymphoma. On admission, computed tomography (CT) scan of the cranium showed no abnormality. The CT was repeated within 48 hours as the patient developed status epilepticus and papilledema; the repeat scan showed characteristics of posterior reversible encephalopathy syndrome (PRES). Association of rituximab with this condition was suspected as there was no recurrence of PRES after receiving two more cycles of CHOP without rituximab. Contrary to previously published case reports, this patient had a delayed clinical presentation