In a com plete randomize design 35 Holstein dairy calves were assigned to five treatments (7 in each treatment) from the day 4 after brith until two weeks post weaning (for 70 days) to study effects of replacing milk fed to suckling calves with probiotic or ordinary yogurt on their performances and health. Treatments included: 1- control (milk without any additives), 2- Milk contains 15% ordinary yogurt, 3- Milk contains 30% ordinary yogurt, 4- milk contains 15% probiotic yogurt and 5- milk contains 30% probiotic yogurt. Calves were fed with milk twice daily in the morning and afternoon that yogurt were added in afternoon milk. During the experiment, calves had ad libitum access to water and starter ration. Starter intake were recorded daily. Body weight was measured at the beginning of the experiment and weekly. Condition of feces was checked twice daily and was scored based on stool consistency. Skeletal growth parameters were measured at days 14, 34 and 56. Blood samples were collected for determination of blood parameters at the ages of 4, 34 and 56 days old. Also for CBC test Blood samples were collected at 42 nd ’s days of the experiment. Results indicated that, Average Daily dry matter intake and total dry matter intake were not affected (p 0.05) by experimental treatments. Average daily weight gain and total weight gain were significantly different (p 0.05) between treatments such that average daily weight gain and total weight gain were significantly (p 0.01) greater in groups fed yogurt than the control. After weaning weight were not affected by treatments. but the groups fed ordinary yogurt had significantly (p 0.05) more weight gain than the probiotic yogurt fed groups. Feed conversion was significantly (p 0.05) improved for the groups fed by yogurt (probiotic and ordinary) than the control. The number of sick days and the Percentage of neutrophils did not differ between treatments. The percentage of lymphocyte significantly (p 0.01) increased in treatment 4 and the groups fed yogurt than the control. Neutrophil to lymphocyte ratio was significantly (p 0.01) decreased in treatment 3 and 4 and also in the the groups fed by yogurt (probiotic and ordinary) than the control. Triglycerides, glucose and total protein did not differ between treatments. Cholesterol was significantly (p 0.001) lower in treatments 2, 4 and 5. HDL was significantly (p 0.05) greater in treatment 2. In days 34 body length was significantly (p 0.05) higher for yogurt groups and it was highest for the group fed probiotic yogurt (p 0.01) and treatment 4 had more Body length (p 0.01). In days 56, withers height was significantly (p 0.05) higher for the groups fed by yogurt than the control group. In days 14 width of the hip bone was significantly (p 0.05) increased in treatment 3, 4 and 5 and was significantly (p 0.01) greater for the groups fed by yogurt than the control group. As a result, yogurt could improve the performance and health of calves, However probiotic yogurt did not seems to have significantly different effects than the ordinary yogurt. Key words: ordinary yogurt, probiotic yogurt, HDL, cholestrol, lymphocyte