A coagglutination (COA) test to detect Candida antigenemia was developed using locally produced Candida antiserum and COA reagent. All 68 controls had normal results. Two patient groups were included in this study. In Group 1, consisting of eight patients, with definite systemic or deep candidiasis proved by repeat Candida isolation, COA detected antigenemia in 100% as against 50% by counterimmunoelectrophoresis (CIE). In Group 2, 9 of 19 patients had respiratory infection; 4 patients revealed antigenemia by COA, 2 of whom had no Candida isolation. In these 2 patients therapy was initiated based on COA results. Of another nine patients with hematologic and malignant diseases, five (56%) revealed antigenemia by COA, three of whom had no Candida isolation; two died and one was discharged against advice. Transient antigenemia was detected by COA in a single patient with ulcerative colitis with Candida isolation. Thus, the COA test was found to be rapid, sensitive, and specific for the detection of Candida antigenemia. Furthermore, it had early diagnostic (seven days) as well as prognostic value, as revealed by response to therapy and decrease in COA titer. Being highly cost effective, this test is recommended as a simple test within the reach of any routine diagnostic laboratory.