An optimized ELISA system for the detection of soybean mosaic virus was developed. Purified anti-soybean mosaic virus IgG, a secondary ovalbumin coat, and a clearly defined optimal concentration of enzyme-conjugated anti-soybean mosaic virus IgG are used. The test detects purified virus, or purified virus added to leaf and seed extracts, at a concentration of 2.5 ng/ml. Various buffers significantly affect detection sensitivity.