A low utilization of antiserum has been reported in gastrin radioimmunoassay with a solid-phase procedure. As solid-phase immunoassays possess several advantages over their soluble counterparts for the assay of many hormones, a solid-phase radioimmunoassay for gastrin was examined. The results showed that this technique was suitable for gastrin determination without being wasteful to antibodies. Sensitivity and precision of the method were comparable to other investigations on gastrin immunoassay, as well as serum gastrin levels obtained for persons with no known gastro-intestinal disease, in patients with pernicious anemia and in patients with Zollinger-Ellison syndrome.