The present study was performed to ascertain the synergistic effects of phytogenic feed additives (PFA-7) supplementation on immune status and haemato-biochemical profile of buffalo calves. The PFA-7 is a mixture of neem seed cake (Azadirachta indica), mahua seed cake (Madhuca longifolia), fennel seed (Foeniculum vulgare), harad (Terminalia chebula), fruit pulp of bahera (Terminalia bellirica), fruit pulp of amla (Phyllanthus emblica) and ajwain seed (Trachyspermum ammi) mixed in 2:2:2:1:1:1:1 proportion. Male buffalo calves (n = 21) having similar age and body weight were allotted to three groups in a completely randomised design. The dietary treatments were viz. T1: control (without PFA-7) and T2 and T3: provided with PFA-7 at 2 and 4% of dry matter intake (DMI), respectively, plus sodium sulphate at 0.06% of DMI. The feeding trial was carried out for 4 months, and serum isolation was done on days 0, 60 and 120 post-feeding. The concentrations of total protein, albumin, globulin, aspartate transaminase and alanine transaminase increased, whereas cortisol and glucose decreased in the supplemented groups as compared to the control. The levels of triglycerides, urea, albumin/globulin ratio, calcium, phosphorus and alkaline phosphatase were not affected by the supplementation of PFA-7. Both cell-mediated and humoral immune response increased in the supplemented groups. The results revealed that PFA-7 positively impacted haemato-biochemical profile and both cellular and humoral immunity of the growing calves. The PFA-7 can be used as an alternative for chemical feed additives in the diet of growing calves.