Genetic diversity of loggerhead turtles, Caretta caretta, nesting on the Kuriat Islands, the most important Tunisian nesting beach (central Mediterranean), was investigated using both nuclear and mitochondrial markers. Allozyme electrophoresis of 63 hatchlings from four different clutches showed a low genetic diversity. The genotypic composition of two clutches did not match Mendelian expectations suggesting the occurrence of multiple paternity. The analysis of 380 bp of the mitochondrial DNA control region revealed no genetic variability. Only one haplotype was described in our sample (N = 16), which corresponds to the sequence of the most common haplotype found on the Mediterranean nesting beaches (CC-A2). The low genetic diversity detected by both mitochondrial and allozyme markers is discussed taking into account available data about past and present situations of loggerhead nesting activity in this site. Adequate conservation measures should be urgently taken to protect the nesting population in this area.