The aim of the study was to determine the prevalence of infectious keratoconjunctivitis on cross-breed dairy farms and to evaluate factors that influence its distribution. A total of 11 dairy farms and one cattle cross-breeding farm in different parts of Arsi region, south-east Ethiopia were clinically and bacteriologically investigated from February 1989 to December 1990. Out of 5221 local zebu and cross-breed dairy animals, 110 were found to have different degrees of infectious bovine keratoconjunctivitis. Of these, 94 (85.5%) were unilateral and 16 (14.5%) were bilateral. The prevalence of the disease was significantly (P < 0.001) influenced by age and breed; high exotic blood level and younger age groups were mainly affected. However, severity of the disease was not significantly associated with age (P > 0.750). Moraxella bovis was isolated from 88 (80%) of the 110 bacteriologically positive cases. Of these isolates, 61 (69%) were haemolytic and 27 (31%) were non-haemolytic strains. Infection with M. bovis was unilateral. Concurrent infections with M. bovis included Actinomyces pyogenes 23 (21%), Staphylococcus aureus 17 (15%), Pasteurella haemolytica nine (8%), Escherichia coli eight (7%) and Proteus spp. four (3.6%).