Certain corticosteroids, including fluorometholone, have been reported to have a low propensity for elevating intraocular pressure. Our clinical impression was that the incidence of IOP increase with fluorometholone may be higher than reported. This study was to determine the incidence and degree of IOP response to 0.1% fluorometholone suspension in 43 patients demonstrated to be responsive to 0.1% dexamethasone sodium phosphate solution. Twenty-six patients (60.5%) had IOP increases of 5 mm Hg or more while receiving fluorometholone, and three patients (7%) demonstrated pressure rises greater than 15 mm Hg. Fluorometholone can significantly raise IOP in a significant number of corticosteroid responders.