In order to understand the magnitude and trends of both under- and over-nutrition problems in Asian countries, we reviewed data available in a number of selected countries. In general, the prevalence of under-nutrition is declining in this region but is still heavy in many countries. The trends varied with complexity of individual countries. In China, the prevalence of underweight, stunting and wasting was 21.6%, 30.5% and 2.6% in children of 0-4 years old (90,662 subjects, 1987) . Another large-scale survey in 1992 (176,976 subjects) presented a prevalence of 17.1% , 33.5% and 4.5%, respectively. Recent studies showed a remarkable improvement in both underweight and stunting. The National Student Survey in 1995, however, showed that the prevalence of under-nutrition was 26.9% for schoolboys and 38.3% for schoolgirls (7-18 yr). There was an increase of 4.7% and 3 .5%, respectively, compared with the results of a similar survey conducted in 1985. The proportion of malnutrition in Chinese adults (BMI < 18.5) was 11.6% in 1982 and 9.0% in 1992 for urban areas, and 12.9% and 8.0% for rural areas, indicating a descending trend over the 10 years. The prevalence of underweight was the highest, over 50% among children below 6 years old, in both Bangladesh and India, between 50% and 20% in Malaysia, the Philippines, Thailand and Vietnam, and below 20% in Mongolia, Kazakhstan and Fiji. It showed a declining trend from the 1970s to the 1990s with an average annual reduction of 0.8 to 1.9 percentage points in these countries. The problem of over-nutrition is emerging quickly in this region, not only in some better-off countries but also in countries in economy transition. In China, the prevalence of overweight and obesity in young adults (BMI > 25) was increased from 9.7% to 14.9% for urban areas and from 6.15% to 8.4% for rural areas in a 10-year period (1982 - 1992), and the prevalence of overweight jumped from 3.38% and 2.75% in 1985 to 7.18% and 8.65% in 1995 for schoolboys and schoolgirls. In India, the increase of overweight and obesity in female adults was 5.0 percentage points from 1989 to 1994. The prevalence of overweight was 24.5% for male and 21.4% for female in Japan (1995), and 28.7% and 26.0% in Malaysia (1990). These results indicate that over-nutrition is a growing problem in this region. Many Asian countries are facing double challenges. They have to deal with both under-nutrition and over-nutrition problems. Among many possible interventions, the further strengthening mass education on healthy diet practice should be emphasized.