To assess the effect of corticosteroid on the establishment of experimentally induced keratomycoses, rabbits were injected subconjunctivally with triamcinolone acetonide on two successive days before inoculation with Candida albicans, Aspergillus fumigatus, or Fusarium solanae. Whereas isolate recovery rates declined steadily in normal control corneas, they remained stable over 15 days in corticosteroid-treated corneas. Clinically, inflammation was equivalent (A fumigatus and F solanae) or significantly less (C albicans; P = .001) until the 10th day. At 15 days, inflammation in corticosteroid-treated corneas was significantly worse in animals infected with A fumigatus (P = .003) or F solanae (P = .02). Inflammatory signs correlated inconsistently with isolate recovery. Pathogenicity of the infecting organism appears to be important in determining the degree to which corticosteroid is able to mask clinical signs of infection while enhancing fungal replication.