Congenital heart disease (CHD) affects nearly 1% of the population, but only few genes involved in human CHD are presently known. Germ-line mutations in the zinc finger transcription factor GATA4 have been associated with familial cases of atrial and ventricular septal defects and pulmonary stenosis. We have screened 99 unrelated Danish patients with different CHD phenotypes to evaluate the prevalence of GATA4 mutations in CHD. No pathogenic mutations were found among the patients, suggesting that GATA4 mutations are relatively rare among CHD patients. Thus, the diagnostic importance of GATA4 mutations may be confined to familial cases or specific subgroups of CHD phenotypes.