In this study longitudinal of the taurine content in the human milk of 23 Korean lacto-ovo-vegetarian women was studied during the lactating periods of the 15th, 30th, 60th, 90th, 120th and 150th day after delivery. The results of the study on primiparae and multiparae studied separately are as follows: 1) The taurine content of the primiparae per 1ml of human milk was 356.1nmole on the 15th day, 238.6 nmole on the 30th day, 249.6 nmole on the 60th day, 148.7 nmole on the 20th day, and 139.6 nmole on the 150th day. There was a significant decrease in the measns. 2) The taurine content of the multiparae per 1ml f human milk was 401.6 nmole on the 90th day, 189.9 nmole on the 120th day, and 159.8 nmole on the 150th day. There was a significant decrease in the measns. 2) The taurine content of the multiparae per 1ml of human milk was 401.6 nmole on the 15th day, 342.3 nmole on the 30th day, 273.2 nmole on the 60th day, 248.6 nmole on the 90th day, 189.9 nmole on the 120th day, and 159.8 nmole on the 150th day. There was a significant decrease in the measns. The multipareas had higher taurine content in every lactating period than the primiparae but there was not a significant difference. The correlation between the changes durinig lactating periods and the taurine content was negative. The correlation coefficient of the primiparae was -0.641 and that of the multiparae was -0.753. The overall correlation coefficient of the primiparae and the multiparae is -0.644, decreasing significantly up to the 150th day.