Early diagnosis of kidney and urothelial cancer requires some new sensitive and specific methods. In this study the diagnostic use of serum alpha 1-acid glycoprotein (alpha 1-AG), coeruloplasmin, alpha 1-antitrypsin (alpha 1-AT), alpha 2-macroglobulin (alpha 2-MG) and albumin in patients with kidney, urinary bladder and upper tract urothelial cancer was evaluated. In kidney cancer patients the serum levels of alpha 1-AG, coeruloplasmin and alpha 1-AT were significantly increased over the controls (p < 0.001), however, albumin was decreased (p < 0.005). Sensitivity was relatively high for alpha 1-AG (85%), albumin (85%) and alpha 1-AT (77%). In patients with urinary tract urothelial cancer alpha 1-AG, alpha 1-AT and coeruloplasmin were also increased but not as much as in kidney cancer. Sensitivity of alpha 1-AG (63%), albumin (75%) and alpha 1-AT (66%) was also lower than in kidney cancer. This study has established the relative importance of alpha 1-AT and albumin determination in patients with kidney as well as with urothelial cancer.