Abstract: Scrum sialic acid level was determined in 133 patients with gynecalogic carcinoma, 75 non-cancerous patients and 539 normal individuals. The results showed that serum sialic acid level was significantly higher in 103 ovarian carcinoma patients than that of the normal controls (P<0.001)，and it was also higher than that of the cerig carcinoma and noncancerous patients (P<0. 001) . Meaanwhile, 62 patients with ovarial and oviduct carc inoma were determined during treatment, among them siailc acid level appeared to decline in 43 patients of clinical remission, and to elevate in 19 patients of clinical nonchanged (P<0.01)，A positiv0 correlation was noticed between the sialic acid changed and the patients Who respnnscd to the treatment, Therefore, it is useful to determination serum sialic acid for diagnosing of ovarian carcinoma and observing curative effects.