The preferential association between Turner's syndrome and congenital heart defects (CHD) have been well known since the first description by Morgagni. There are few studies about the different cardiologic problems stemming from different chromosomal patterns of X monosomies. We reviewed a large series of 136 patients with Turner syndrome without cardiologic preselection, 29 of whom had some kind of CHD (21.5%). Partial anomalous pulmonary venous drainage (PAPVD; 2.9%), aortic valve disease (stenosis and/or incompetence) (AoVD; 5. 1%), aortic coarctation (AoCo; 4.4%), and bicuspid aortic valve (BicAo; 14.7%) are much more frequent in Turner's syndrome than in the normal population, with the difference being statistically highly significant. In our cases, only the 45, X subjects showed severe CHD and multiple lesions, whereas the X-ring pattern was associated with an elevated prevalence of BicAo. Patients with X-deletion showed no signs of congenital heart malformations. Eleven patients, all with 45, X pattern, and significant CHD, underwent cardiac surgery at a mean age of 7.7 +/- 5.3 years (range 7 days-18 years) without complications. At follow-up of 3-18 years (8.6 +/- 5. 2), we were unable to observe any type of evolution of the remaining untreated cardiovascular anomalies.