Several studies report that tendons can regenerate after harvesting. These studies have been performed especially in patellar and hamstring tendons. At our institution, 10 cm length of full thickness peroneus longus tendon has been harvested to reconstruct torn anterior cruciate ligament since 1997 as a different graft source. The aim of this study was to investigate whether the peroneus longus tendon used the anterior cruciate ligament reconstruction has a regeneration potential or not. Twelve patients, who had originally undergone harvesting of the peroneus longus tendon for the primary surgery of the anterior cruciate ligament reconstruction, underwent magnetic resonance imaging (MRI). Images of both legs were acquired simultaneously with the use of the scanner's extremity coil, as we aimed to compare harvested peroneus longus tendon with the other leg's peroneus longus tendon (healthy side) for evaluation of the regeneration potential. The average age of the patients was 31 years. There were eight right and four left legs. The average time interval was 52 months between ligament surgery and MRI. In all patients, a varying amount of the regeneration of the peroneus longus tendon was seen on the MRI images. Although the extent of PLT regeneration in proximal sections seemed better than in mid- and distal sections, there was no statistical difference between sections (P = 0.130). These data show that the peroneus longus tendon has a regeneration potential after harvesting for anterior cruciate ligament reconstruction.