The dairy cow transition period is associated with increased incidence of metabolic disorders. Ketosis is the most prevalent metabolic disease and approximately 10–25% of cows experience clinical ketosis following calving. We hypothesize that a compromised gastrointestinal barrier (a.k.a. leaky gut) and subsequent lipopolysaccharide (LPS) infiltration may play a key-role in ketosis etiology. Study objectives were to retrospectively characterize biomarkers of leaky gut during the transition period in healthy and clinically diagnosed ketotic (urine acetoacetic acid >15 mg/dL) cows. Blood samples from lactating Holstein cows (n = 164, parity 2–7; from a commercial herd) were obtained at 21, 14, and 7 d antepartum (±3 d) and 3, 7, 10, and 14 d postpartum (±1 d). Cows were retrospectively categorized into one of 2 treatments: healthy (H; n = 24; no diagnosed health disorder) and ketotic (KET; n = 22; cows diagnosed only with ketosis). KET cows had reduced milk production compared with H (10%, P < 0.01). Antepartum circulating LPS in KET cows was increased (129%, P = 0.02) compared with H, and they tended to have increased NEFA (70%; P = 0.08) when compared with H. Postpartum KET cows had increased NEFA (49%; P < 0.01), BHBA (16%; P = 0.01), SAA (75%; P = 0.04), haptoglobin (273%; P = 0.03), and L-lactate on d 3 (74%: P = 0.02) and tended to have higher LPS binding protein (LBP; 4854 vs. 3569 ng/mL; P = 0.07), when compared with H. Postpartum circulating insulin was decreased (11%; P = 0.02) in KET cows compared with the H. The postpartum LPS area under the curve (a measure of total LPS exposure over time) tended to be decreased in KET cows (P = 0.06), which may be explained by treatment differences in LBP and its role in LPS removal. In summary, blood bioenergetics and gut integrity biomarkers indicate that ketosis may be closely associated with biomarkers of leaky gut during the transition period.