In our cross-sectional survey of the residents of homes for the elderly in 2 Hong Kong districts—Shatin and Tai Po—we found that 3.4% of the subjects had Parkinson9s disease (PD). There was no sex difference in the disease rate. We also conducted a case-control study to determine the associated factors of PD. We found that subjects with residence of long duration in rural areas, with engagement in farming, with previous use of herbicides and pesticides, and with habitual consumption of raw vegetables had a statistically significantly increased risk of PD. This study tends to support the hypothesis that environmental factors directly or indirectly related to agricultural activities are associated with the development of PD.