The aim of the current research was to evaluate the effects of linseed oil (LO) nutritional supplementation on the growth performance of broiler chicks, in addition, their effects on immunological and biochemical parameters of serum, total antioxidant capacity, intestinal morphology, mortality percentage, and estimates of economic efficiency. Over the course of the five-week trial period, 150 (Ross 308) one-day-old chicks were separated into five groups, each consisting of three replicates (10 chicks/replicate). The chicks were fed five different experimental diets with varying quantities of oil (0% oil, 1 (SBO and 1% LO), 2% LO, and 3% LO, respectively). For assessment, four chicks from each replication were randomly used. The findings showed that while there was no discernible variation in feed intake across all groups, broiler chicks’ body weight (Bw) increased (P<0.05) when linseed oil was added to their feeds. Supplementing linseed oil resulted in a significant (P<0.05) improvement in dressing % and carcass attributes. The breast muscle of broilers fed linseed oil had considerably (P<0.05) greater values of poly unsaturated fatty acids and n-3 polyunsaturated fatty acids than that of the control groups. Additionally, there was a significant (P<0.05) decrease in the amounts of triglycerides, cholesterol, LDL, VLDL, and TAC. Nevertheless, consuming meals containing linseed oil led to a significant (P<0.05) increase in serum levels of HDL-c, total protein (TP), globulin (GL), and GSH-Px. Additionally, giving broiler chickens linseed oil enhances their immunological response to the Newcastle vaccine. The current study showed that adding linseed oil to chick feeds increases immunological response, body composition, serum biochemical parameters, intestinal morphology and growth performance beside decreasing mortality ratio. However, it is not economically feasible when matched with control groups (0% oiland 1% SBO).