A Western blot method (WB) was adapted for rapid screening of antibodies against coxsackie virus B1-B6 in sera from patients with newly diagnosed insulin-dependent diabetes mellitus, myocarditis or febrile syndrome of suspected coxsackie viral aetiology. The use of a mixture of all 6 coxsackie virus B serotypes as the common antigen permitted a very rapid and inexpensive detection of antibody-positive sera for preliminary diagnosis and further detailed assay. Comparison of the results with those obtained in parallel run virus-neutralization tests showed a higher sensitivity and comparable specificity of WB.