The objective of this study was to search for screening biomarkers of metritis in transition dairy cows. Blood samples were collected from the coccygeal vein once per week before morning feeding from 100 multiparous Holstein dairy cows during −8, −4, disease diagnosis, and +4 and +8 wk relative to parturition. Six healthy cows (CON) and 6 cows that showed clinical signs of disease were selected for intensive serum analyses. Concentrations of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor (TNF); haptoglobin (Hp), serum amyloid A (SAA), and lipopolysaccharide binding protein (LBP); and nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHBA) were measured in serum by ELISA or colorimetric methods. Health status, feed intake, and milk yield were monitored for each cow during the whole experimental period. Data were processed statistically by MIXED procedure of SAS 9.2. Results showed that cows affected by metritis had greater concentrations of lactate (2,901 vs 2,251 ± 183 μmol/L, P = 0.04), IL-6 (111 vs 27 ± 13 pg/mL, P = 0.01), TNF (0.72 vs 0.19 ± 0.11 ng/mL, P = 0.01), and SAA (13,441 vs 8,517 ± 1,517 μg/mL, P = 0.03) in the serum vs CON. Most interestingly, elevated concentrations of all 4 variables were observed at −8 (lactate: 3,902 vs 2,455 μmol/L, P = 0.03; IL-6: 87 vs 19 pg/mL, P = 0.05; TNF: 0.77 vs. 0.34 ng/mL, P = 0.09; SAA: 17,960 vs 8,448 μg/mL, P = 0.02) and −4 (lactate: 3,311 vs 2,162 μmol/L, P = 0.03; IL-6: 166 vs 48 pg/mL, P = 0.02; TNF: 1.02 vs 0.27 ng/mL, P = 0.03; SAA: 6,003 vs 3,461 μg/mL, P = 0.03) wk before the occurrence of metritis compared with those of CON cows. The disease also lowered the overall milk production (38.18 vs 42.16 ± 1.48 kg/d, P = 0.01) and feed intake (36.87 vs 39.81 ± 1.30 kg/d) as well as milk fat (3.56 vs 3.88 g/kg, P = 0.10) and fat:protein ratio (1.10 vs. 1.38, P = 0.05) and was associated with greater SCC (44,700 vs. 29,250 ± 4,880 cells/mL, P = 0.05). In conclusion, metritis affected serum concentrations of several variables related to innate immunity and carbohydrate metabolism that might serve to monitor health status of transition dairy cows. More research is warranted to validate these data.