An 11-year-old girl developed a corneal ulcer five days after sustaining a corneal abrasion from a fishline sinker. After more than three weeks, the epithelial defect had closed, but superficial stromal opacities in a ring-like distribution had not cleared on topical gentamicin, prednisolone 1% and atropine. Several scrapings disclosed the presence of branching hyphae on smear, eventually identified as Nocardia asteroides by culture. Although sensitivity studies suggested that subconjunctival ampicillin and hourly sodium sulphacetamide would constitute effective treatment, resolution was only partial on this regimen. Only when penicillin G drops were added did the cornea clear maximally and the epithelium heal.