The vaccination process and immunological status of chickens during their life period have great importance in the poultry industry. We aimed in the current study to evaluate the effect of ProbChick® on the immunological status of broiler chickens after vaccination with Newcastle vaccination using the LaSota strain. A total of 200 one-day-old chicks were divided randomly into five groups. The first group is the control group, while the second group consumes ProbChick® with drinking water. The third group was vaccinated with the Newcastle vaccine (LaSota strain), and the fourth group was vaccinated with the Newcastle vaccine after 7 days. The ProbChick® was consumed. The fifth group was vaccinated with the Newcastle vaccine and consumed ProbChick® on the same day. The result showed that ProbChick® enhances the weight gain, food conversion ratio, and relative weight of the bursa of Fabricius and spleen. In addition, ProbChick® will enhance the antibody titer if it is added to drinking water on the same day of vaccination and give suitable antibody titer compared to control groups and in comparison, to a group where it is added to drinking water after 7 days of vaccination. We conclude that adding ProbChick® to the broiler at 1 g/litter of drinking water at the same vaccination by Newcastle vaccine using the LaSota strain will enhance the immune response during and after vaccination. This will improve the efficiency and titer of antibody production.