Background: To explore the relationship between hyponatremia and medical disease in eldly patients with intertrochanteric fractures . Methods: 76 elderly patients with intertrochanteric fracture were included, in which there were 54 cases complicated with medical disorder. Serum sodium levels was detected at time point of 1d and 3d after admission. We investigated the incidence of hyponatremia in patients with or without medical disease, observed the relationship of hyponatremia occurrence with age, fracture type and gender. Results: 38 of 76 patients had hyponatremia, included 22 casese with mild hyponatremia and 16 casese with moderate hyponatremia . When compared with normonatramic patients, there was no statistically significant in gender(P=0.454), position(P=0.645) , age stratification(P=0.106) ,or fracture type(P=0.973) . There was no statistically significant in patients with or without cardiovascular disease and patients with or without diabetes mellitus (P=0.646 and P=0.262). The incidence of hyponatremia in casese with lung disease was higher than without it (X2=4.415,P=0.042). Conclusion Hyponatremia is commom in elderly patients with intertrochanteric fracture ,most of those were mild or moderate hyponatremia. Hyponatremia is more likely to occur in patients associated with lung disease.