Hyperketonemia (HYK) is frequently observed in high-producing dairy cattle and has been associated with suboptimal health and performance. Traditionally, HYK has been defined by blood β-hydroxybutyrate (BHB) of >1.2 mmol/L, although cows vary in their clinical response to HYK. Thus, our objective was to evaluate the association between HYK occurring in early lactation with milk yield and reproductive performance in Holstein dairy cows throughout an entire lactation. We hypothesized that elevated BHB in the first 10 d postpartum is not necessarily detrimental to all cows. Blood BHB was measured in 1,108 cows from 6 herds in Minnesota between 3 and 10DIM. Cows were followed for their entire lactation, until next calving or culling. Health and performance data were collected from herd management software. In addition to classification based on blood BHB (HYK+ and HYK−), cows were further classified into remaining (REM, cows that reach subsequent calving) or culled (CUL, cows that were sold or died during lactation). Cox proportional hazard was performed to analyze time to pregnancy, adjusting for herd and parity effects. Milk yield was analyzed by ANOVA accounting for repeated measures and adjusting for herd effect; separate models were created for primiparous and multiparous cows. Disease events and DIM at culling were applied to all models and removed using backward stepwise elimination. Overall prevalence of HYK was 11.2% (range 3.2% to 20.3%). Although the hazard ratio (HR) for pregnancy by 300 DIM for HYK+ (REM and CUL combined) cows was 0.64 (95% CI: 0.47–0.86) when compared with HYK− (REM and CUL combined) cows, the REM HYK+ HR was 5.65 (95% CI: 4.65 - 6.87) times higher than CUL HYK− cows. Similarly, no difference was observed when comparing milk production for combined HYK+ and HYK− multiparous cows. However, REM HYK+ cows produced, on average, 5.1kg/day (95% CI: 3.47 - 6.11) more milk than the CUL HYK+ cows. These findings suggest that HYK does not affect all cows in a similar fashion.