Since the introduction of radioiodinated metaiodobenzylguanidine in 1980, considerable research has been performed, both in the chemical field and in medical sciences. However, despite the wide use of radioiodinated metaiodobenzylguanidine, knowledge about its pharmacology is still limited. This paper reviews the biodistribution and pharmacokinetics, drug interactions, cytotoxicity and dosimetry of radioiodinated metaiodobenzylguanidine. Iodine-131 metaiodobenzylguanidine therapy is in general well tolerated, but its effectiveness needs improvement. Also whole-body dosimetry as part of treatment planning needs to be improved. Future prospects on these items are included in this review.