The constant monitoring of dairy cow metabolism is extremely important, especially in the period immediately after calving, when the animals face the consequences of negative energy balance. The concentration of beta-hydroxybutyrate is one of the reliable indicators of metabolic status. The aim of this work was to evaluate the effect of beta-hydroxybutyrate concentration in the blood on selected parameters of production, reproduction, and health of Holstein dairy cows. The limit for subclinical ketosis was set to >1.2 mmol/L of beta-hydroxybutyrate in blood. Furthermore, the effects of lactation number, season, and year of assessment were added to the model equation. The results showed that high beta-hydroxybutyrate concentration in blood is associated with poor reproduction parameters (worse insemination interval and service period) and lower milk production. However, the results were ambiguous in relation to the somatic cell count and the occurrence of selected diseases (mastitis and ovarian cysts). Moreover, the effect of seasonality on the evaluated parameters was also confirmed (P<0.05), while assessed years were similar in most parameters. It can be concluded that the assessment of beta-hydroxybutyrate concentration as an indicator of potential ketosis is important and can be a suitable parameter for routine monitoring as it influences milk production, reproduction, and cow's health.