Since December 1988, we have measured the TAG 72 serum levels in 326 patients with different carcinomas, especially breast, gastrointestinal and ovarian, using a RIA kit. With a cut-off value of 5 U/mL, a specificity of 100% in the controls and an overall sensitivity of 22% in the neoplastic patients was obtained, with the highest positivities in ovarian (63%) and gastric (58%) carcinomas. Therefore, TAG 72 can be associated with other tumor markers for these latter neoplasms.