This study was undertaken to estimate seasonal variation of riboflavin status and investigate the relationship between riboflavin intake and its biochemical status in rural women. Dietary intake was measured by determining both 24hr recall method and conventient method. The riboflavin intake was also estimated by food frequency method. Ribofiavin biochemeical status was assessed by erythrocyte glutathione reductase activity coefficient(EGR AC) and urinary riboflavin excretion. All information was repeatly collected in three seasons ; farming season (June), harvest season(October), nonfarming season(February). Mean daily riboflavin intake was below RDA for Koreans in all seasons. Cereal & pulse, vegetable were the primary sources of riboflavin intake and provided above 60% of the total dietary riboflavin intake in all seasons. Riboflavin biochemical status was significantly different among seasons(EGR AC P<0.005, 24hr urinary riboflavin excretion P<0.05), and riboflavin biochemical deficiency was highest in February. The mean values of EGR AC revealed riboflavin deficiency in all seasons. However the mean values of urinary riboflavin excretion were within the normal range except 24hr urinary riboflavin excretion in February. On the basis of EGR AC criteria, 44.7% of subjects were at risk of deficiency in June, 44.7% in October, 81.6% in February. Result of individual riboflavin status assessed by EGR AC or 24hr urinary riboflavin excretion criteria was quite alike. Urinary riboflavin excretion per gram of creatinine underestimated riboflavin deficiency. Significant correlations were observed among biochemical indexes. It also appeared that riboflavin intake measured by food frequency method showed significant correlation with biochemical indexes, especially high correlation with EGR AC (P<0.001). The results indicated that the prevalence of riboflavin deficiency seems to be high among rural women in all seasons and the inadequacy of dietary riboflavin intake was reflected in the abnormalcy of riboflavin biochemical status assessed by EGR, AC. Therefore EGR AC seems to be more sensitive measure of impaired riboflavin status compared to urinary excretion.