Objectives This study aimed to investigate whether a growth factor and a cytokine midkine (MK) can be a new biomarker for the diagnosis and treatment of unexplained female infertility (UFI) cases. Methods Serum (S), follicle fluid (FF), and cumulus cells (CCs) of the patients aged 20–42 years, diagnosed with male factor (MF) and UFI were used. Patients underwent Intracytoplasmic Sperm Injection (ICSI). The anti-Müllerian hormone (AMH) and MK levels with other hormone levels (FSH, LH, E2, PRL, INHB, TSH), the oocyte and embryo qualities, the fertilization and pregnancy rates, and cumulus cells (Cell number and ultrastructure, apoptosis rate) were evaluated. Student-T-test was performed and p Results The lowest numbers of CCs were found at UFI (p Conclusions MK can not be accepted as a new biomarker for the diagnosis and treatment monitoring of UFI cases.