This study identified differences in plasma metabolites among three groups of dairy cows: type I ketotic (K1), type II ketotic (K2), and healthy control cows (C). 50 cows with two or three parities were selected at 7-28 days postpartum. Cows were classified as type I ketotic (K1, 20 cows), type II ketotic (K2, 20 cows), or healthy control cows (C, 10 cows). Plasma metabolomic profiles were analyzed by 1H-nuclear magnetic resonance technology ( 1 H NMR). The data were processed by principal component analysis and orthogonal partial least-squares discriminant analysis (OPLS-DA). Results-The results revealed that OPLS-DA was more effective at distinguishing amongst the three groups. Additionally, there were seven different metabolites between K2 and C, 19 different metabolites between K1 and C, and 24 different metabolites between K1 and K2. Therefore, the combination of 1 H-NMR and multivariate statistical analyses can effectively distinguish the differential metabolites among the K1, K2, and C groups, thereby providing important information on the pathogenesis, early diagnosis, and prevention of type I and type II ketosis in dairy cows. H NMR-based AbstractThis study identified differences in plasma metabolites among three groups of dairy cows: type I ketotic (K1), type II ketotic (K2), and healthy control cows (C). 50 cows with two or three parities were selected at 7-28 days postpartum. Cows were classified as type I ketotic (K1, 20 cows), type II ketotic (K2, 20 cows), or healthy control cows (C, 10 cows). Plasma metabolomic profiles were analyzed by 1H-nuclear magnetic resonance technology ( 1 H NMR). The data were processed by principal component analysis and orthogonal partial least-squares discriminant analysis (OPLS-DA). Results-The results revealed that OPLS-DA was more effective at distinguishing amongst the three groups. Additionally, there were seven different metabolites between K2 and C, 19 different metabolites between K1 and C, and 24 different metabolites between K1 and K2. Therefore, the combination of 1 H-NMR and multivariate statistical analyses can effectively distinguish the differential metabolites among the K1, K2, and C groups, thereby providing important information on the pathogenesis, early diagnosis, and prevention of type I and type II ketosis in dairy cows.