Drainage surgery may be required in patients who have previously demonstrated a corticosteroid-induced rise in intraocular pressure. This report presents three patients who had complicated secondary glaucoma and who demonstrated an intraocular pressure increase in response to topical cortico-steroid drugs, despite the presence of a functioning Molteno implant. On discontinuation of the corticosteroid drugs, the intraocular pressure returned to normal levels. Although the mechanism for this observation is unknown, these cases suggest that the trabecular meshwork may still continue to drain aqueous in some patients, despite the presence of bleb over the footplate of a Molteno implant. In predisposed patients who require drainage surgery, Molteno implantation therefore may not prevent the rise in intraocular pressure secondary to the use of topical corticosteroid drugs.