Salmonella is one of the main causes of foodborne disease related to poultry product consumption and a public health issue. Efforts should be done to control and reduce Salmonella load in poultry production. The use of bacteriophages could be an effective solution to limit these infections in broilers and subsequently its transfer to humans.This study evaluates the preventive and therapeutic effect of phages, administered on drinking water, on Salmonella infection in chicks. A cocktail of 6 phages with in vitro demonstrated efficacy against a variety of Salmonella serotypes was used.At first it was demonstrated that the phages were able to persist in chickens’ gut for at least 3 days without Salmonella challenge. Then the prophylactic and therapeutic potential of the cocktail was evaluated in vivo on 50 chicks challenged by Salmonella Enteritidis LA5 at 5.104 CFU/chicks by oral gavage at 7 days of age. The cocktail was administrated before the challenge via the drinking water during the first 6 days of the chicks’ life and was also administrated 2 days before the end of the trial. Salmonella enumeration and phage identification and counting were investigated during the 4-week trial. Results show that up to 4 days post infection, phages have a preventive effect and that they are able to significantly reduce Salmonella colonization in the ceca and feces by 2 to 4 log (p<0.05). Unfortunately, this effect was not persistent and Salmonella level raised 7 days post infection. During this period, only 2 out of 6 phages were detected in the different gut segments. However, the 2nd administration of the cocktail 2 days before the trial’s end, again reduced the Salmonella loads by 1 log in the ceca. This treatment showed encouraging results regarding preventive effect and ability of phages to protect against Salmonella infection during critical steps of poultry production. Further work is needed to improve the treatment and prevent the recovery of Salmonella infection.