Abstract Pseudomonas aeruginosa is an important cause of dermal, pulmonary and ocular disease. Our studies have focused on P. aeruginosa infections of the cornea as a major cause of blinding microbial infections. The infection leads to an influx of innate immune cells with neutrophils making up to 90% of recruited cells during early stages. We previously reported that the proinflammatory cytokines IL-1a and IL-1b were elevated during infection. Infected Il1b−/− mice developed more severe corneal disease that is associated with impaired bacterial killing as a result of defective neutrophil recruitment to the corneas. We also reported that neutrophils are an important source of IL-1b and IL-1a. To examine the role of IL-1a in Pseudomonas aeruginosa keratitis, we inoculated corneas of C57BL/6 (WT), Il1a−/−, Il1b−/− and Il1a−/−Il1b−/− (DKO) mice with 5×10^4 ExoS expressing P. aeruginosa (PAO1 strain). We identified neutrophils and monocytes as the main producers of IL-1a which peaked at 24 hours post infection (hpi). Depletion of neutrophils or monocytes led to more severe corneal disease and higher bacterial burden. Il1b−/− and DKO mice have significantly higher bacterial burden that was consistent with impaired neutrophil and monocyte recruitment to the corneas. Surprisingly, Il1a−/− mice had the opposite phenotype with significantly less bacteria than WT mice. There were no significant differences in neutrophil recruitment. However, we hypothesize that Il1a−/− neutrophils have enhanced antimicrobial functions that resulted in more effective bacterial killing which we are addressed by RNA sequencing of neutrophils isolated from WT or Il1a−/− corneas. Supported by grants (EP) RO1: EY18612 and (BR) F31: EY032312-01