AbstractWe have analysed 194 Belgian CF chromosomes using a variety of techniques: ΔF508 was detected by polyacrylamide gel electrophoresis; dot blotting of PCR products was used to identify the mutations G542X, 1717‐1 G → A, and N1303K; molecular defects in exons 2, 3, 4, 5, 6b, 7, 11, 12, 13, 14a, 14b, 17b, 19, 20, and 21 were screened for by DGGE. We identified 17 mutations, which accounted for 94.3% of the Belgian CF chromosomes. Four novel mutations and a novel polymorphism were characterized. The detection of such a high proportion of Belgian CF mutations is important in understanding the functional role of the molecule and in improving prenatal and genetic diagnosis of CF. © 1993 Wiley‐Li