A post-enrichment enzyme-linked immunosorbent assay (ELISA) on nitrocellulose membrane (NCM-ELISA) is described for the detection of Ralstonia solanacearum in latently infected potato tubers. The polyclonal antiserum specificity was significantly improved by adsorption with cross-reacting bacteria. The detection efficiency after enrichment was compared with those of nucleic acid spot hybridization (NASH), double-antibody-sandwich immunoassay (DAS-ELISA) and plating on modified Kelman’s medium. After 48 h of incubation of the tuber extracts with modified SMSA broth at 30°C, sensitivities of post-enrichment NCM-ELISA, DAS-ELISA and NASH were similar. As few as 10cells mL−1 were detected in either inoculated or naturally infected tuber extracts. Of 255 field samples, no cross-reactivity of NCM-ELISA was observed. Post-enrichment NCM-ELISA thus provides a reliable and sensitive low-cost method that is rapid and easy to use, making it suitable for assessing susceptibility of breeding lines to bacterial wilt, ecological studies and seed quality control in developing countries. © 1999 Wiley. All rights reserved.