Abstract: An experiment was conducted to study the effects of different levels of kaolin, bentonite and zeolite on broiler performance in 6 weeks. Four hundred and forty eight day-old broilers of male Ross 308 strain were allocated to 7 treatments with four replications and 16 broilers in each. The experiment was carried out in a completely randomized design. Treatments were control and 1.5, 3% of kaolin, bentonite and zeolite. Treatments with 3% zeolite and bentonite was significantly (p<0.05) increased weight gain during the 1st and 6th weeks, 1.5% kaolin and zeolite, significantly (p<0.05) increased weight gain in 5th and 6th weeks compared to the control, respectively. Treatments 1.5% bentonite in 4th and 5th weeks and 1.5% zeolite and 3% bentonite in 5th week was significantly (p<0.05) increased feed intake compared to the control. Feed conversion ratio in diets with 3% kaolin in the 1st and 2nd weeks and 3% zeolite in the 1st week was significantly (p<0.05) improved compared to the control. There was no significant (p>0.05) differences in internal organs and fecal pH between trial groups and control. Fecal moisture in treatments with 1.5% kaolin, 3% bentonite and zeolite was significantly (p<0.05) different from control. Growth rate in treats containing 3% kaolin at 0-3 week and 1.5% zeolite, 1.5% kaolin and 3% kaolin, bentonite and zeolite at 0-6 week was more than control (p<0.05). The results demonstrated that adding silicate minerals in diet, improve performance of broiler chickens.