This study evaluates coagulation profiles of single ventricle (SV) patients in relationship to liver function, hemodynamic variables and outcome. Twenty-six children with SV anatomy were included. Advanced coagulation profiles, invasive preoperative hemodynamic parameters and clinical course were retrospectively analyzed. Median (interquartile range) age and weight at the time of blood sampling was 25.5 (31) months and 10.5 (6.9) kg. Sixteen patients (16/26; 62%) showed decreased antithrombin and/or protein C (PC) and/or free protein S (PS) function and/or free PS antigen. Two patients showed abnormal activated PC resistance ratio due to heterozygous factor V Leiden mutation and 1 heterozygous prothrombin G20210A mutation. Group comparison (abnormal coagulation profile [group 1; n = 16] versus normal coagulation profile [group 2; n = 10]) showed longer postoperative hospitalization time (p = .04), longer postoperative catecholamine support (p = .01), a higher incidence of thromboembolic events (p = .04), and chylothoraxes (p = .007) in group 1. In 5 (31%) of 16 group 1 patients, thromboembolic complications occurred: cerebral stroke (n = 1), intestinal ischemia (n = 2), thrombus formation in inferior caval vein (n = 1), and pulmonary vein (n = 1). Abnormalities in coagulation parameters are common in SV patients. Coagulation abnormalities constitute a preoperative risk factor and affect postoperative course.