Background: Salmonella is one of the most important zoonotic agents known to infect humans and a wide range of animals, including poultry. Salmonella Infantis has been one of the 15 most frequently isolated serovars throughout the world. Despite its clinical importance, little is known about the molecular characteristics of S. Infantis strains from Iran. OBJECTIVES: The purpose of this study was mainly to type a number of S. Infantis isolates obtained from Iranian poultry flocks in the last decade by pulse-field gel electrophoresis (PFGE). METHODS: Forty five Salmonella Infantis isolates, mostly from poultry origin, were subjected to PFGE according to protocol of the CDC PulseNet. RESULTS: PFGE revealed 27 pulsotypes and eight clusters among 45 isolates based on the number of observed bands among the pulsotypes. The distribution of 45 isolates among the 27 pulsotypes was variable and included from one to nine isolates. One pulsotype included nine (20%) isolates. The genotypic similarity among 45 isolates was more than 90%. CONCLUSIONS: This study showed the value of PFGE in determining the genotypic similarity among S. Infantis isolates. The high genotypic similarity shown by PFGE among the S. Infantis isolates of this study suggested that the majority of S. Infantis isolates studied may have descended from a common ancestor that has differed little and is responsible for the contamination of poultry flocks and possibly humans as well