The small intestine of the common genet is the habitat of Taenia parva (Taeniidae), a common parasite whose intermediate host is Apodemus spp. (Rodentia). Here we divided the small intestine of 51 common genets into sections and analysed them separately. Cestodes were classified into four categories: larval, pre-adult, adult and gravid specimens. A total of 4,443 individuals were recovered and classified: 543 larval stages, 2,326 pre-adults, 872 adults and 702 gravid specimens. A double analysis was performed by checking the distribution of the parasite along the digestive tract and comparing this distribution with reproductive fitness. This is the first study to test the border effect on the distribution of T. parva in its habitat. We also tested and demonstrated the Ideal Free Distribution Model (IFM model). A non-random distribution was found, with the lowest parasite frequencies in the top and the bottom portions of the small intestine. Maturity classes of cestodes vs. intestine portion were tested and no differences between portions were detected. We also analysed seasonal changes in parasite frequency. Log-linear analysis showed that the mean frequency of cestode occurrence per individual host was higher during winter, followed by spring, autumn and summer.