Objective:To improve the diagnostic level of lower extremity deep venous thrombosis ( LEDVT ) and decrease the rate of missed diagnosis.Methods:23 clinical cases which admitting diagnosed with LEDVT but final diagnoses weren’t LEDVT were retrospectively analyzed in our hospital between 2000 and 2006.Results:Of these 23 cases with missed diagnosed

13 cases were gynecology tumor

1 case was adenomyosis

3 cases were rectal cancer

2 cases were lung cancer

2 cases were carcinoma of bladder

1 case was prostatic carcinoma

and 1 case was malignant lymphoma in ingina.Conclusion:clinicians should pay attention to question the case history when their patients get lower extremity deep venous thrombosis

especially to those whom are inconspicuous predisposing cause.