Ovarian cancer is one of the most lethal gynecological malignancies. Mitochondria are the predominant source of reactive oxygen species (ROS) in the cell. Besides mitochondria nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX) enzymes generate a significant amount of ROS in the cell. The present work establishes an interesting link between NOX4 enzyme (which is an important source of reactive oxygen species “ROS”) and PHB1 (as a holdase type chaperone in mitochondrial stress). The current study was conducted on 60 patients with ovarian tumours (benign, borderline and malignant) and 20 healthy volunteers (as a control group). NOX4 expression was assessed by TaqMan® real time gene expression assay, while cellular expression of prohibitin was evaluated by immunohistochemistry. There was a significant increase in prohibitin expression from benign cystadenoma to malignant tumors. In addition, there was an increase in NOX4 expression. In conclusion, over-expression of PHB1 and NOX4 in malignant ovarian tissues suggest that PHB1 is associated with tumorigenesis via activation of NOX4 enzyme with subsequent release of ROS in the cells.