Objective: Hyperosmolar therapy is one of the core medical treatments for brain edema and intracranial hypertension, but controversy exists regarding the use of the most common agents, mannitol, and hypertonic saline. the authorsconduct the study to compare the effect of equimolar and equivolume dose of 20 percent mannitol solution and of 3 percent hypertonic saline solution in the treatment of stroke patient with sustained elevated intracranial pressure. Method: Design: Parallel, randomized, controlled trial. Results:The two treatments equally reduced ICP during the experiment. At 120 mins after the start of the infusion, ICP was reduced from 38.9 + or - 11.26 to 23.75 + or - 8.7 (mean + or - sd) in the mannitol group vs. 37.4 + or - 10.77 to 22.44 + or - 4.16 in the HSS group. No major changes in blood pressure, pulse were found after each treatment. Hypertonic saline caused a significantly greater increase in doride concentration (p 0.05) than mannitol. Both treatments caused elevation of serum osmolarity but not significantly. Condusion: Infusion of 20 percent mannitol is as effective as 3 percent hypertonic saline solution in decreasing ICP in patients with stroke. Pretreatment factors, such as serum sodium, systemic hemodynamics, and brain hemodynamics, thus should be considered when choosing between mannitol and hypertonic saline for patients with increased ICP, (ICP