Technical Abstract: Infectious bovine keratoconjunctivitis, also known as pinkeye, is an economically important disease in cattle. The objective of this study was to detect quantitative trait loci associated with infectious bovine keratoconjunctivitis in offspring from a Brahman x Hereford sire. The sire was mated to Hereford, Angus and F1 cows to produce 288 offspring in 1994, and mated to MARC III (¼ Hereford, ¼ Angus, ¼ Red Poll, and ¼ Pinzgauer) cows in 1996 to produce 259 offspring (547 animals total). Infectious bovine keratoconjunctivitis was diagnosed by physical examination in 36 animals of the family. Records included unilateral and bilateral frequency, but not severity. Records were binary; “zero” for unaffected and “one” for affected cattle. A putative quantitative trait loci for infectious bovine keratoconjunctivitis was identified on chromosome 1, with a maximum F-statistic (F = 10.15; P = 0.0015) at centimorgan 79 of the linkage group. The support interval spanned centimorgans 66 to 110. There was also evidence suggesting the presence of a quantitative trait loci for infectious bovine keratoconjunctivitis on chromosome 20, with a maximum F-statistic = 10.35 (P = 0.0014) at centimorgan 16 of the linkage group. The support interval ranged from centimorgan 2 to centimorgan 35. No clear candidate gene can be identified as responsible for infectious bovine keratoconjunctivitis on these chromosomes.