To investigate the folate status of the Chinese in Taiwan, the plasma and red blood cell (RBC) folate levels were measured in this study. The blood samples were collected from 1993 to 1996 when the Nutrition and Health Survey in Taiwan (NAHSIT) was carried out. Subjects of both sex, aged 4 years old and above representing the population in Taiwan were studied. Folate contents in plasma and RBC collected in the first year were measured by both microbiological assay and chemiluminescent enzyme immunoassay. Both the average plasma and RBC folate in male were significantly (P＜0.05) lower than those of female (8.2±4.1 vs. 11.1±4.6ng/ml plasma; 504±244 vs. 589±234ng/ml RBC). The population aged from 13 to 18 had the poorest folate status among all age groups. Only 58% male and 72% female adolescents had normal plasma folate levels. The percentage of marginal deficiency was higher in male group compared to female group and increased with age. The percentage of folate deficiency and marginal deficiency with low plasma folate was highest in the population of mountain area. People living in east coast and Penghu islands had higher percentages of RBC folate deficiency and marginal deficiency, respectively. The correlation between plasma and RBC folate levels and the dietary frequency of folate-rich food suggested that increased intakes of dark green vegetables, fresh vegetables, citric fruits, other fruits, squash, pickled vegetables and seaweed may have beneficial effect on folate status. In addition, plasma folate levels were reciprocally correlated with systol1c pressure in this study. Therefore, whether dietary folate intake and folate status play a role in vascular disease in Taiwanese population remains of interest to be investigated and explored.