Salmonella is a major cause of foodborne illness worldwide. Most cases of human salmonellosis are associated with the consumption of contaminated of eggs and egg-related products. Globally Salmonella Enteritidis is the most predominant serovar responsible for egg associated Salmonella outbreaks. In Australia Salmonella Typhimurium (S. Typhimurium) is a major cause of egg associated outbreaks although, mechanism of egg contamination by S. Typhimurium has not been investigated. In this study, laying hens were orally challenged at week 14 with either S. Typhimurium phage type 9 (PT9) (T group) or S. Typhimurium PT9 and S. Mbandaka in combination (MT group). Faecal samples of infected hens were processed for Salmonella isolation and enumeration by most probable number (MPN) method at day 1, 3, 6, 9, 12, week 3, 5, 7, 9, 11, 13 and 15 post infection. Eggs laid during week 5, 7, 9, 11, 13 and 15 were tested for the presence of Salmonella on egg shell surface and egg internal contents. Salmonella was recovered from faeces of infected hens on all days but the overall mean Salmonella counts were significantly higher in MT group (32.47±3.12) compared to T group (21.58± 3.20). The overall frequency of egg shell contamination was also higher (18.43%) in MT group as compared to T group (5.66%). None of the internal egg contents were positive for Salmonella throughout the study. The results of this study suggest that S. Typhimurium PT9 was able persist in gut of infected laying hens until week 15 post infection. The shedding of S. Typhimurium on egg shells was variable across 15 weeks of post infection.