The Keokuk County Rural Health Study has completed two rounds of data collection since funding began in 1990. Members of 1,000 households, comprising approximately 2100 men, women, and children have completed medical screening, in-person interviews, and environmental assessments in their homes and on their farms. To date, 43 manuscripts based on study data have been published in peer-reviewed journals, an additional manuscript is in press, and 21 sub-studies, using the KCRHS study population or data, have been initiated by outside investigators. Round 3 data collection began in December 2006 and will continue until we have enrolled 750 households. As in Rounds 1 and 2, through medical screening, in-person interviews, and environmental assessments, we are collecting data on respiratory disease, injuries, hearing and vision impairment, and neurobehavioral outcomes. We will assess these outcomes in relation to agricultural and other occupational exposures.