The objective was to determine the effect of feeding zeolite A during the prepartum period on peripartum serum mineral status. Holstein cows (n = 55) entering second or greater lactation were assigned randomly to one of 2 dietary treatments starting 21 d before expected calving; control (CON): 40% corn silage, 33% wheat straw, and 27% concentrate or experimental (EXP): CON plus zeolite A (X-Zelit, Protekta Inc./Vitfoss) at 3.3% of DM, targeting 500 g/d as-fed. Blood was collected 1×/wk from enrollment until 7 d before expected calving, daily through 7 DIM with 2 samples within the 24 h of calving, and 3x/wk from wk 2 to 4. Data were analyzed in SAS v. 9.4 with repeated-measures ANOVA using the MIXED procedure. The difference in prevalence of subclinical hypocalcemia (SCH; serum Ca <8.5 mg/dL) between treatments by day and chronic SCH (cSCH; all serum samples between 0 and 3 DIM with Ca <8.5 mg/dL) was tested with Fisher’s exact test. There was a treatment by day effect on serum Ca (prepartum: P = 0.06, postpartum: P < 0.001), P (prepartum: P = 0.04, postpartum: < 0.001) and Mg (prepartum: P < 0.01, postpartum: P < 0.001). Cows fed EXP had higher prepartum serum Ca (9.88 ± 0.10 vs. 9.26 ± 0.10 mg/dL, P < 0.001), lower P (3.20 ± 0.13 vs 6.30 ± 0.12 mg/dL, P < 0.001) and lower Mg (1.70 ± 0.03 vs. 1.84 ± 0.03 mEq/L, P < 0.01). Cows fed EXP had higher postpartum serum Ca (9.33 ± 0.09 vs. 8.60 ± 0.09 mg/dL, P < 0.001) and lower P (3.70 ± 0.13 vs 4.32 ± 0.12 mg/dL, P < 0.001). The prevalence of hypocalcemia was higher in cows fed CON at −3, −1, 0.25, 0.75, 2, 3, and 15 DIM and tended to be higher at 6 DIM. The largest difference in hypocalcemia prevalence was at 0.75 DIM; 90% of cows fed CON vs. 31% of cows fed EXP. No cows fed EXP had cSCH vs. 35% of CON cows and half of the EXP fed cows had no SCH through 3 DIM compared with 3% of CON cows (P < 0.001). Cows fed EXP had higher serum Ca and lower serum P and Mg with differences being most pronounced during the immediate peripartum period. Feeding zeolite A during the prepartum period resulted in markedly improved Ca status during the periparturient period.