Posterior reversible encephalopathy syndrome (PRES), is an acute, neurotoxic state. It is a very rare clinico-neuroradiological entity, and it is a complication of multiple clinical conditions. The association of PRES with toxemia in pregnancy is established. In this article, the authors discuss the case of a 22-year-old woman, gravida 1, 36-week pregnant, with extensive, bilateral white matter hypodensity, predominantly involving the parieto-occipital lobes region. These changes were highly suggestive of posterior reversible encephalopathy. This case report demonstrates that early treatment with control of blood pressure seizures can reverse this condition and also prevent progression to an irreversible damage, thus emphasizing the need for early diagnosis and treatment.