Our objective was to evaluate effects of diet starch content and fermentability (SF) on inflammatory response and oxidative stress markers during the early postpartum (PP) period and its carryover effects. Fifty-two multiparous Holstein cows were used in a randomized block design experiment with a 2 × 2 factorial arrangement of treatments. Diets were formulated to 22% (LS) or 28% (HS) starch with dry ground corn (DGC) or high moisture corn (HMC) as the primary starch source. Treatments were fed from 1 to 23 d PP and then switched to a common diet until 72 d PP to measure carryover (CO) effects. Diets were formulated to 22% forage NDF and 17% CP for the treatment period (TP) and 20% forage NDF, 17% CP and 29% starch for the CO period. Blood was collected before feeding (0730 h) once a week during TP and every second week during the CO period. Blood plasma was analyzed by colorimetry for concentrations of haptoglobin (HAP), albumin and reactive oxygen species (ROS), with LPS-binding protein (LBP) and TNF-α evaluated during the TP only. Data were analyzed separately for TP and CO using a Mixed Model including treatment interactions with time. During the TP, treatments interacted to affect concentrations of TNF-α, HAP and LBP (P < 0.07), with HMC increasing their concentrations for HS (9.29 vs. 8.42 pg/mL, 0.54 vs. 0.41 mg/mL and 5.85 vs. 4.67 μg/mL, respectively) and decreasing their concentrations for LS (5.88 vs. 11.3 pg/mL, 0.29 vs. 0.44 mg/mL and 4.41 vs. 6.02 μg/mL, respectively) compared with DGC. Effects of treatments diminished over time for LBP and HAP with no differences by the end of the TP. Opposite treatment interaction was observed for albumin, with HMC tending to decrease albumin for HS (3.25 vs. 3.34 g/dL) and increase albumin for LS (3.38 vs. 3.29 g/mL; P = 0.13) compared with DGC. HMC tended to increase ROS compared with DGC (57.5 vs. 52.0 RFU/μL; P = 0.07). Treatment effects diminished for all variables during the CO period. Results during the TP suggest that feeding LS-DGC and HS-HMC elicited a more pronounced inflammatory response, with ROS increased by HMC treatments.