Abstract Aim: To describe the relationship between the resistance index of the common hepatic artery and liver function tests in children undergoing bone marrow transplantation. Materials and Methods: We analysed prospectively the results of 106 Doppler ultrasound examinations of the common hepatic artery from 31 bone marrow transplant patients, 16 of whom had normal liver function. The aetiology of the liver dysfunction in the other 15 patients was veno-occlusive disease ( n=7), unknown ( n=3), hepatic graft-versus-host disease ( n=2), hepatitis ( n=2), or cholestasis ( n=1). We assessed the relationships between the hepatic arterial resistance index (HART) and the results of the serum glutamic-oxaloacetic transmainase (SGOT), serum glutamic-pyruvic transaminase (SGPT), alkaline phosphatase (ALK), lactate dehydrogenase (LDH) and serum albumin (ALB) assays and calculated HARI break-point values that might distinguish patients with liver disease from patients with the normal liver function. Results: The significant break point ( P<0.05) of the HARI was 0.55 for SGOT, SGPT and ALK. LDH was associated with a break point of 0.53. Resistance indices for the common hepatic artery below the break-point values predicted liver dysfunction with specificities of 81%, 80%, 92% and 93%, respectively. There was no significant relationship between liver function tests and ALB levels. Conclusion: If below 0.55, the hepatic arterial resistance index is a non-invasive indicator of liver dysfunction in children undergoing bone marrow transplantation.