This study aimed to investigate the effect of different levels of dietary threonine (i.e. 100%, 110% and 120% of Ross recommendations) and potassium (i.e. 0.85% and 0.94% of diet) on performance, immune response, and bone parameters broiler chickens. Three hundred one-day-old male broiler chickens (Ross 308) were randomly assigned to 1 of 6 dietary treatments in a completely randomized design with a 3 × 2 factorial arrangement. Growth performance was not affected by dietary treatments. Birds fed diet containing 120% threonine and high potassium level were exhibited a lower immune response to phytohemagglutinin-P (PHA-P) as compared to control group (P < .05). Addition of 120% threonine with 0.94% potassium decreased heterophil percentage and heterophil to lymphocyte ratio and increased lymphocyte percentage (P < .05). Tibia and femur width and ash, Ca and P percentage of tibia, and breaking strength of bones were not influenced by dietary potassium level, whereas the width of tibia and femur was increased in broiler chickens received diet containing 120% threonine and 0.94% potassium compared to control group (P < .05). It is concluded that broiler chickens FI during starter period, cell mediated immune response and blood hematology were influence by dietary threonine and potassium interaction.