<p>Mistletoes and other parasitic plants pose serious problems for forests because of the impacts on their host trees. This emphasizes the importance of understandingthese relationships in the light of changing environmental conditions and forest management. This study investigates the effects of pine mistletoe (<i>Viscum album</i> subsp. a<i>ustriacum</i> Wiesb.) on the physiological traits and plant nutrients of Anatolian black pine (<i>Pinus nigra</i> Arnold subsp. <i>pallasiana</i> (Lamb.) Holmboe). Fifteen uninfected (control) [thin class control (TC) and medium class control (MC)], and fifteen moderately infected [thin class infected (TI) and medium class infected (MI)] Anatolian black pine trees were sampled from both thin and medium diameter classes. The study revealed that mistletoe-infected trees exhibited significant reductions in chlorophyll content and mineral nutrients, alongside increases in proline, malondialdehyde (MDA), and hydrogen peroxide (H₂O₂), particularly in the medium-diameter class. These findings suggest that mistletoe infection caused a notable decline in photosynthetic efficiency and nutrient absorption, affecting plant health. The principal component analysis showed a clear distinction between infected and uninfected trees, further confirming the detrimental impact of pine mistletoe infection on Anatolian black pine.</p>