Since 1994, an epidemic of conjunctivitis caused by Mycoplasma gallisepticum has been reported in wild house finches (Carpodacus mexicanus) in the eastern United States. Over the past ten years, many field studies have been published on this wild bird epidemic, centering on epidemiology, disease dynamics and risk factors. However, there is a paucity of published studies that focus on the clinical immunology and pathology of M. gallisepticum infection in captive finches or other avian species. We hypothesized that the severity of conjunctivitis, the primary clinical sign of M. gallisepticum infection in house finches, is positively correlated with conjunctival cytological changes and the presence and abundance of mycoplasmal organisms. We further hypothesized that these cytologic changes can be quantified using standard cytologic staining. To test this hypothesis, captive house finches were experimentally infected with M. gallisepticum. Sequential conjunctival smears were made for cytology, and conjunctival swabs were collected for M. gallisepticum polymerase chain reaction prior to and at predetermined time points post-infection. Preliminary data analysis supports our working hypothesis.