This research aspires to demonstrate how the stage of lactation influences the content of macroelements in the Lacaune sheep milk. The research was conducted with 30 Lacaune sheep in their fourth lactation during the early (60 days), middle (120 days), and late lactation stages (180 days). The macroelement concentration (Ca, K, Na, and Mg) of the Lacaune sheep milk was determined by the ICP. As lactation progressed, a significant increase in the concentrations of Mg and Na and a significant decrease in K were observed in the Lacaune sheep milk. A stability of Ca and P concentrations during lactation was demonstrated by the lack of significant variation in the Lacaune sheep milk, based on the stage of lactation. A significant positive correlation was detected between Ca:Mg, Ca:P, and K:P, as well as a significant negative correlation between Mg:K and K:Na. The obtained results prove a significant effect of lactation stage on the content of most macroelements in the Lacaune sheep milk, except Ca and P, which should be included in the research scheme.