Seventy-five psychiatric inpatients were evaluated with respect to their Miranda-related abilities using Grisso’s (1998, Instruments for assessing understanding and appreciation of Miranda rights. Sarasota, FL: Professional Resource Press) instruments and Goldstein’s (2002, Revised instruments for assessing understanding and appreciation of Miranda rights) revision to determine: whether different versions of Miranda warnings translate into differences in understanding; the influence of psychiatric symptoms, diagnostic categories, and IQ upon Miranda comprehension; and the relative performance of persons with psychiatric impairment on Miranda-relevant abilities. Results indicated that although the Miranda language used in Goldstein’s revision generally showed lower grade reading levels and higher reading ease scores than Grisso’s original instruments, this did not translate into improved understanding. In addition, psychiatric symptoms were negatively correlated with Miranda comprehension, even after controlling for IQ. Finally, results revealed that psychiatric patients’ understanding and appreciation was substantially impaired compared to Grisso’s adult validation samples, and was roughly comparable to Grisso’s juvenile validation sample. Implications of these results for policy reform are discussed.