Objective: Tadalafil is a selective phosphodiesterase type-5 inhibitor with a long half-life. It has a dual function in ischaemic and re-perfused tissues, i.e. vasodilatation and anti-oxidant effects. These features of tadalafil distinguish it from other anti-oxidants. We investigated the dual effect of tadalafil on ischaemia and reperfusion injury in the rat ovary.Material and Methods: We established five study groups. Group 1 (n=6): sham-operated; group 2 (n=6): torsion; group 3 (n=6): torsion and Tadalafil; group 4 (n=6): torsion/de-torsion; and group 5 (n=6): torsion/de-torsion and tadalafil. Ovarian samples were harvested from animals and evaluated in terms of histopathologic changes, tissue malondialdehyde (MDA) concentrations, lactate production, and plasma cyclic guanosine monophosphate (cGMP).Results: Follicular degeneration, oedema, haemorrhage, and inflammatory cells were significantly decreased in group 5 in comparison with group 4. Group 2 and group 3 were compared in terms of vascular congestion and haemorrhage; these parameters were significantly decreased in group 3. In addition, significantly decreased MDA and lactate concentrations were observed in group 5 in comparison with group 4. Increased cGMP concentrations were detected in group 3 and group 5.Conclusion: We conclude that tadalafil might be useful in protecting the ovary against ischaemia and reperfusion injury. In the evet of ovarian torsion, it will provide a greater therapeutic effect than only performing de-torsion of the ovary or using other anti-oxidant agents. (J Turk Ger Gynecol Assoc 2020; 21: 35-40)