To evaluate farmers' workload during harvesting grapes in summer, this study investigated farmers' physiological, psychological responses, work postures and thermal environment around in the field. This field study was conducted in the Anseong County of Kyonggi Province at the end of August. Five career farmers (1 male, 4 females) volunteered as subjects. Three of them were over their sixties. During harvesting grapes in the field, physiological responses were monitored continuously. 1. Air temperature (T/sub a/), air humidity(H/sub a/), black globe temperature(T/sub g/), air velocity and WBGT around the grape field were 26.9℃, 77.7%RH, 32.8℃, 0.08㎧ and 26.3℃, respectively. Because farmers started the harvesting task in early morning, thermal environments weren't conditions to give farmers severe heat strain. 2. The percentage of the work postures was larger in order of standing, walking, and bending one's back posture. Particularly, the percentage of standing posture with raising both arms above shoulder of two farmers was up to 29% and 61% of the total work duration. 3. Rectal temperature (T/sub re/), mean skin temperature (T/sub sk/), clothing microclimate temperature (T/sub cl/) on the chest and the back, heart rate (HR) and energy expenditure (EE) were 37.2℃, 33.1℃, 32.0℃, 32.4℃, 88bpm and 1.3 Kca1/㎡/min respectively. In the point of these physiological results, we evaluated that the harvesting task was a moderate work. 4. All farmers expressed‘hard, hot, humid and slightly uncomfortable’ at the end of works for each subjective questionnaire. The grape harvesting tasks were not evaluated as a very hard work in the point of physiological work standards. But we considered 1) inappropriate work posture (standing posture with raising both arms above shoulder) and 2) farmers' age as burden factors. These findings suggest that adding adequate protective clothing/equipments for farmers may contribute to maintain their body temperature within the normal range, stabilize HR and decrease psychological strain.