The autonomic nervous system plays an important role in the human heart. Activation of the cardiac sympathetic nerve system is a cardinal pathophysiological abnormality associated with the failing human heart. Myocardial imaging using ¹²³I-metaiodobenzylguanidine (MIBG), an analogue of norepinephrine, has been applied to investigate the activity of the predominant neurotransmitter of the sympathetic nervous system. ¹²³I-MIBG uptake in the myocardium is known to be reduced after the onset of heart failure, and improves when heart failure is controlled; therefore, treatments for heart failure may be assessed based on improvements in ¹²³I-MIBG scintigraphic parameters. In this review, we summarized studies that have focused on the use of cardiac sympathetic nerve imaging using ¹²³I-MIBG scintigraphy to evaluate the effectiveness of pharmacological treatments in heart failure patients.