OBJECTIVE To determine intergroup and intragroup consensus for interdisciplinary perceptions of dietitians' legal responsibility for lethal dietary prescription errors. DESIGN Survey research was conducted by a mail questionnaire containing four hypothetical cases in which the dietitian provides a lethal amount of dietary potassium for an anephric patient. SETTING Of the 90 New York State end-stage renal disease facilities contacted, 64 returned one or more questionnaires. SUBJECTS/SAMPLES Usable questionnaires were tabulated from 51 registered dietitians, 39 registered head nurses, and 43 physician-medical directors. MEASURES Consensus was recognized when 60% or more of the responses occurred in one extreme collapsed and dichotomized category of "yes" or "no" regarding the dietitian's legal responsibility. STATISTICAL ANALYSES PERFORMED Intergroup and intragroup consensus levels were compared by frequency, mean, standard deviation, and Scheffe test of differences. RESULTS The triad groups met varying levels of consensus on all four scenarios, with dissenting opinions by nurses on two scenarios. The dietitians and the physician-medical directors had mirror-image perceptions that the dietitian was not legally accountable for two cases of following foreseeably lethal dietary prescriptions "as written." Eight dietitians viewed the dietitian as legally nonculpable for causing a patient's death because of the dietitian's sole incompetence or carelessness in making a serious calculation error. Nurses met the highest levels of agreement and perceived the dietitian to be legally accountable for all four cases. The nurses, in contrast to the dietitians and physician-medical directors, held opinions of dietitian legal responsibility as consistent with the standard of care expectations of prudent health care professionals defined by professional malpractice jurisprudence. APPLICATIONS/CONCLUSIONS The data indicate that to protect both the patient and the professional, there is a notable need for greater understanding dietetics jurisprudence.