Fasciola hepatica and Fasciola gigantica are two trematodes (liver flukes) that cause water- and food-borne disease Fasciolosis. Many animals are involved in the life cycle of the Fasciola spp., such as sheep, cattle, and camels, and humans are the definitive host. This work investigated the prevalence of Fasciola among imported and local slaughtered sheep and the relation between infection rate and seasons of the year. A total of 720,290 local and imported sheep (251,701 and 468,489, respectively) were slaughtered in a Jeddah slaughterhouse (Western region of Saudi Arabia) over the periods of 2017-2018, 2018-2019, and 2019-2020. In the three years of inspection, the infection rate at slaughter was higher among imported than local sheep. In 2017-2018, both local and imported sheep had the highest level of infection in the spring and the lowest in the winter. However, in 2018-2019, the highest rate of infection for both was documented in the summer and the lowest in the winter. Lastly, in 2019-2020, the highest rate of infection for local sheep was observed in the summer of 2020 and the lowest rate of infection was observed in the spring of 2020. Among imported sheep, the highest rate of infection was in the summer and the lowest was in winter for both 2019 and 2020. To control this disease, there is the need to apply for successful integrated programs and practice adaptive management techniques.