Pharmacologic inhibition of fibroblast proliferation and scar formation remains an important consideration in many ophthalmologic surgical procedures. Such inhibition is particularly important in glaucoma filtration surgery. A sustained release system for 5-fluorouracil (5-FU) using ethylene vinyl acetate copolymer (Elvax) was characterized in vitro. 5-FU was incorporated into Elvax discs of 4 mm diameter. Discs were coated to allow sustained and predictable release over a 14 day period. Alteration of coatings, which act as rate-controlling membranes, allowed variation in the pattern of 5-FU release from the core which acts as the drug reservoir. This system for the sustained release of 5-FU may prove valuable in glaucoma surgery where the suppression of cellular proliferation is desired. The non-inflammatory nature of Elvax suggests this compound may provide an alternative means of 5-FU delivery.