In a group of 23 patients with advanced liver cirrhosis we have found a statistically significant positive correlation (r = 0.746; p less than 0.0001) between fibronectin and prealbumin levels measured in plasma by immunonephelometric methods and found significantly lower than in healthy controls (p less than 0.001). On the contrary, no correlation of fibronectin neither to albumin nor to the presence of an enlarged spleen was observed. Since the sensitivity of prealbumin as an index of liver function is believed to be higher than that of albumin, our results support the view that the decreased fibronectin in advanced cirrhotics is mainly due to their liver failure, an enlarged spleen playing only a minor role.