Familial dysautonomia (FD) patients frequently experience debilitating orthostatic hypotension. Since physical countermaneuvers can increase blood pressure (BP) in other groups of patients with orthostatic hypotension, we evaluated the effectiveness of countermaneuvers in FD patients. In 17 FD patients (26.4 ± 12.4 years, eight female), we monitored heart rate (HR), blood pressure (BP), cardiac output (CO), total peripheral resistance (TPR) and calf volume while supine, during standing and during application of four countermaneuvers: bending forward, squatting, leg crossing, and abdominal compression using an inflatable belt. Countermaneuvers were initiated after standing up, when systolic BP had fallen by 40 mmHg or diastolic BP by 30 mmHg or presyncope had occurred. During active standing, blood pressure and TPR decreased, calf volume increased but CO remained stable. Mean BP increased significantly during bending forward (by 20.0 (17- 28.5) mmHg; P = 0.005) (median (25th - 75th quartile)), squatting (by 50.8 (33.5- 56) mmHg; P = 0.002), and abdominal compression (by 5.8 (- 1- 34.7) mmHg; P = 0.04) - but not during leg-crossing. Squatting and abdominal compression also induced a significant increase in CO (by 18.1 (- 1.3- 47.9) % during squatting (P = 0.02) and by 7.6 (0.4- 19.6) % during abdominal compression (P = 0.014)). HR did not change significantly during the countermaneuvers. TPR increased significantly only during squatting (by 37.2 (11.8- 48.2) % ; P = 0.01). However, orthopedic problems or ataxia prevented several patients from performing some of the countermaneuvers. Additionally, many patients required assistance with the maneuvers. Squatting, bending forward and abdominal compression can improve orthostatic BP in FD patients, which is achieved mainly by an increased cardiac output. Squatting has the greatest effect on orthostatic blood pressure in FD patients. Suitability and effectiveness of a specific countermaneuver depends on the orthopedic or neurological complications of each FD patient and must be individually tested before a therapeutic recommendation can be given. Since physical countermaneuvers can increase blood pressure (BP) in other groups of patients with orthostatic hypotension, we evaluated the effectiveness of countermaneuvers in FD patients. In 17 FD patients (26.4 ± 12.4 years , we monitored heart rate (HR), blood pressure (BP), cardiac output (CO), total peripheral resistance (TPR) and calf volume while supine, during standing and during application of four countermaneuvers: bending forward, squatting , leg crossing, and abdominal compression using an inflatable belt. Countermaneuvers were initiated after standing up, when systolic BP had fallen by 40 mmHg or diastolic BP by 30 mmHg or presyncope occurred. During active standing, blood pressure and TPR decreased, calf volume increased but CO remained stable. Mean BP increased significantly during bending forward (by 20.0 (17-28.5) mmHg; P = 0.005) (median (25th - 75th qua Squatting and abdominal compression (by 50.8 (33.5- 56) mmHg; P = 0.002), and abdominal compression (by 5.8 (-1.34.7) mmHg; P = 0.04) also caused a significant increase in CO (by 18.1 (-1.3- 47.9)% during squatting (P = 0.02) and by 7.6 (0.4- 19.6)% during abdominal compression (P = 0.014) TPR increased significantly only during squatting (by 37.2 (11.8- 48.2)%; P = 0.01). However, orthopedic problems or ataxia prevented several of the patients from performing some of the countermaneuvers. , bending forward and abdominal compression can improve orthostatic BP in FD patients, which is achieved mainly by an increased cardiac output. Squatting has the greatest effect on orthostatic blood pressure in FD patients. Suitability and effectiveness of a specific countermaneuver depends on the orthopedic or n eurological complications of each FD patient and must be individually tested before a therapeutic recommendation can be given.