Aceuthobium oxecedri M. Bieb is an aerial dicotyledonous parasite on branches or stems and is an important forest pathogen. It is most widely distributed dwarf mistletoe in the northern hemisphere, and among hosts it mainly infects the species of Juniperus (Hawksworth 1972) During British India, Brandis (1906) and Parker (1924) reported it on juniper but its pathological significance was brought up recently by Jamal and Beg (1974) while conducting a survey of the diseases of forest trees. According to Zaka (1977) about 36 percent of the trees in Sasnamana forest are infected. The only known control method for the control of the pruning of infected brunches. But this causes damage to the host. To develop new methods of control efforts are being made all over the world to collect basic physiological information about the host-parasite relationship. The present investigation is in the same direction and aims to explore the diurnal fluctuations in water balance parameters of this mistletoe in relation to those of its host, under natural conditions.