Introduction. The identification of biological markers that indicate an increased risk for the development or recurrence of endometrial cancer (EC) in obese women might be useful for decreasing EC mortality and morbidity. Glucose-regulated protein 78 (GRP78) is a major protein of the endoplasmic reticulum expressed in all normal cells. Overexpression of GRP78 has been reported to be a tumoral biomarker. Increased detection of GRP78 is positively correlated with the tumoral stage and prognosis. This study aimed to identify a correlation between intraperitoneal fat, plasma GRP78 levels, and EC. Materials and Methods. Two groups of patients were included in the study: group I, 44 patients diagnosed with EC, and group II, 44 patients without gynecological pathology or inflammatory disorders. Visceral fat was determined by ultrasound and plasma GRP78 levels were measured. Results. Plasma GRP78 levels were significantly higher in patients with EC compared to the control group. Intraperitoneal fat was in a positive linear correlation with the plasma GRP78 level (p < 0.0001). Conclusion. The measurement of the GRP78 level associated with the determination of intraperitoneal fat can be a useful predictor for EC.