The objectives of this retrospective observational study were to determine the association between dry matter intake (DMI) pre- (−14 d to −1) and postpartum (1 to 28 d) and postpartum diseases [retained placenta (RP), metritis (MET), mastitis (MAST), ketosis (KET), and displaced abomasum (DA)] within 28 d postpartum; and to estimate the risk of disease postpartum based on DMI prepartum. Data involving 294 cows from 7 studies were collected. The data were analyzed with the MIXED and GLIMMIX procedures of SAS. Random and repeated variables were cow and day relative to calving, respectively. Models were adjusted for parity, BCS, treatment, study, and interaction between disease and other covariates. Variables with P ≤ 0.05 were considered significant. Cows that had RP ate less on d −3 (RP × day P = 0.01) and on d 5, 7, 8, 12, and 19 (RP × day P = 0.10). Cows that had MET ate less on d −3 and −2 (MET × day P = 0.03) and ate less postpartum (P < 0.01). Cows that had MAST ate less prepartum (P = 0.02) and in the first 14 d postpartum (MAST × day P < 0.01). Cows that had KET ate less pre- and postpartum (P < 0.01). Intake of cows that had DA did not differ prepartum (P = 0.70) but they ate less postpartum (P < 0.01). Cows with at least one disease ate less pre- and postpartum (P < 0.01). Moreover, for each kg decrease in DMI in the last week prepartum, there was an increase of 28% in the odds of having KET (OR = 1.28; CI = 1.15–1.41; P < 0.01), and 24% in the odds of having at least one disease (OR = 1.24; CI = 1.13–1.34; P < 0.01) postpartum. However, DMI was not associated with the odds of having MAST (OR = 1.09; CI = 0.95–1.23; P = 0.23), RP (OR = 1.04; CI = 0.86–1.22; P = 0.66), MET (OR = 1.08; CI = 0.97–1.19; P = 0.14), or DA (OR = 1.07; CI = 0.82–1.32; P = 0.6). Collectively, these data suggest that there is an association between DMI pre- and postpartum and postpartum diseases, and that a reduction in DMI prepartum predisposes cows to disease postpartum.