A simple bidirectional allele-specific PCR method is described for determining the -1082 A and G alleles in the interleukin-10 (IL-10) promoter region. This polymorphism is associated with IL-10 production capacity, and it is thus interesting to see whether different infectious and autoimmune conditions are associated with it, With our method, the A and G alleles may be studied simultaneously in a single PCR reaction, as amplification of the different alleles is performed by using 3'-mismatched and partly overlapping allele-specific upstream and downstream primers around the -1082 site. The fast and simple method described here is especially suitable for large-scale association studies. Copyright (C) 2001 S. Karger AG, Basel.