1．The present paper deals with the age and the growth of Lutjanus sanguineus (C. & V.) by means of age characteristics. The samples were taken by Taiwan bull trawlers from the catch of 960 fish in the Gulf of Tonkin and 410 fish in Northern Sunda Shelf from April 1973 to March 1974. The results are summarized as follows: 2. Among opercle, scale, and vertebra with regard to the age characteristics of L. sanguineus, the ring on centrum of vertebra is the most observable. 2. Since (a) every vertebra has the same ring number and similarity of relative position of ring on centrum, (b) the growth rate of the middle part is more steady than that of anterior and posterior regions along the vertebral column, and (c) the vertebral length and the centrum diameter of the 13rd-15th vertebrae are moderate with small variance, the 14th vertebra is selected for ring reading. The 13rd and 15th vertebrae are used only if the 14th one was damaged. 3． (a) The larger the fish grow, the more the number of rings. (b) Individuals with the same ring number show the corresponding position of ring groups on centrum. (c) The ring-radius composition are nearly separated between any two successive ring groups and their mean ring-radius are different. The above indications show a high regularity of rings once ntrum that it is reasonable to use vertebrae as an age characteristics. 4．The relationship of centrum radius (R)-fork length (L) is expressed by L=aR(superscript b), thus: The Gulf of Tonkin: L=0.8379R^0.9099 Northern Sunda Shelf: L=0.6363R^0.8908 (R:mm×15,L:cm) Following the comparison of the difference in regression lines, ln R-ln L relationships of two samples show insignificant difference between the regression coefficients, but significant difference between the adjusted means. 5.According to the monthly fluctuation in the rate of marginal increment, one ring is formed per year and the time of ring formation is from April to May in bothsamples. 6.The calculated fork length at the time of ring formation is shown as follows: The Gulf of Tonkin: l1 l2 l3 l4 l5 l6 l7 l8 l9 l10 l11 20.76 30.27 38.75 46.04 52.21 57.05 61.50 64.99 69.05 72.67 75.38 cm. Northern Sunda Shelf: l1 l2 l3 l4 l5 l6 l7 l8 l9 l10 21.57 31.57 40.96 48.92 54.87 60.11 66.10 70.49 74.04 76.76 cm 7. Using von Bertalanffy's growth equation for fork length, the following results areobtained: The Gulf of Tonkin: l(subscript t)=92.67(1-e(superscript -0.1417(t+0.8185)) Northern Sunda Shelf: l(subscript t)=96.54(1-e(superscript -0.1484(t+0.6698)) (lt:cm,t:year). Comparing these two growth equations, the growth rate for fork length in Northern Sunda Shelf sample is better than that in the Gulf of Tonkin. 8. The body weight(W)-fork length (L) relationship is expressed by W=aL(superscript b), thus: The Gulf of Tonkin: W=0.0326 L^(2.8023) Northern Sunda Shelf: W=0.0250 L^(2.8709)(W:g,L:cm) Significant difference is found in regression coefficients when the regression lines of ln W onln L are compared. 9. Using yon Bertalanffy's growth equation for body weight, the results are as follows: 26．The Gulf of Tonkin: W(subscript t)=10596.71(1-e(superscript -0.1417(t+0.8185))^(2.8023) 27．Northern Sunda Shelf: W(subscript t)=12469.13(1-e(superscript -0.1484(t+0.6698))^(2.8709)(W(subscript t):g,t:year) Comparing these two equations, the increasing in body weight from the Northern Sunda Shelf samples is better than that from the Gulf of Tonkin.