Carcinoembryonic antigen (CEA) and alpha fetoprotein levels (AFP) were assayed by enzyme-labelled immunoassay in 75 cases of gastrointestinal (GI) and primary hepatic malignancies. Mean CEA levels were found to be significantly higher (p<0.005) in metastatic non-operative group of GI malignancies (range 5.32 nglmL to 175.2 nglmL) as compared to early pre-operative cases (range 1.25 nglmL to 33.2 nglmL) and post-operative cases (range 1.41 nglm L to 22.24 nglmL). Varia ble levels of AFP were visualised in 12 cases of primary hepatic malignancies with eight cases having values less than 100 nglmL. When both CEA and AFP were assayed simultaneously, the markers were helpful in differentiating cases of primary hepatic malignancies with low levels of CEA from 3 cases of secondaries in the liver where CEA levels were found to be highly raised (80.4 nglmL to 146.4 nglmL). To evaluate the variation of CEA and AFP levels in different patients having same stage of the disease, immunological monitoring for the functions of T and B cells was carried out by estimation of cytoklne, i.e. interleukin-l alpha (lL-Ia), interleukin-2R (I1-2R) and various immunoglobulins. IL-Ia and 1L-2R levels were significantly higher (p<0.05) in the groups of patients having higher CEA and AFP. This indicates an important T cell (THI and TH2) function in the tumour antigen production. MJAFII997;