The bovine corneal opacity and permeability (BCOP) assay, originally developed by Gautheron (1992) and Sina (1995) has been used as an in vitro eye irritation screen for industrial hygiene, product development and safety testing. It has recently been validated as a screen for corrosive or severe irritation by ICCVAM and ECVAM. The assay measures changes in corneal opacity, and increases in permeability to fluorescein after chemical exposure. Since Curren and Evans (2000) proposed the use of histopathology to detect potential corneal injury, where the mode of chemical action might not induce opacity and permeability changes, histopathology has been used in BCOP studies for nearly a decade. Although the state of the negative control corneas at the end of the BCOP assay has been characterized histologically, no studies have been conducted to determine if there are artifactual changes in the cornea associated with the collection and storage of the enucleated eyes, or the BCOP methodology. Corneas were excised and fixed at various steps in the assay process, at the time of collection of freshly enucleated eyes, after refrigerated transport, and at the end of the BCOP assay. Corneas were fixed in 10% buffered formalin, embedded in paraffin, H&E stained and the corneas evaluated using light microscopy. Stromal thickness was measured primarily at the central cornea. No remarkable artifacts were observed in the corneal epithelium and endothelium as a result of the various conditions, and the corneal stroma appeared very similar histologically in all cases. The thickness of the corneas collected immediately after enucleation were approx. 600 to 650 µm; corneas collected after the refrigerated transport prior to the BCOP assay were approx. 675 to 775 µm, and typical negative control corneas at the end of the BCOP assay range from 680 to 800 µm. These results show that the corneas undergo minimal artifactual changes as a result of refrigerated transport and the BCOP assay procedures.