In-person cognitive evaluations can be costly and labor intensive in geographically widespread populations. Reliable telephone instruments that screen for cognitive status would greatly facilitate epidemiologic and other longitudinal studies. We evaluated the reliability of the Blessed Information-Memory-Concentration (IMC) test when administered by telephone. Eighty-four subjects with a wide range of cognitive abilities were administered the Blessed IMC twice over a 3-week interval. Forty-nine of the subjects were administered the test both by telephone and in-person, and 35 of the subjects were tested twice by telephone. Spearman's rank correlation was used to compare scores of the different administrations (.96; P < .001) and to examine test-retest reliability (.96; P < .001). The Blessed Telephone IMC (TIMC) test exhibits excellent reliability both when compared to in-person administration as well as in test-retest results. The Blessed TIMC appears to be a practical instrument for population and longitudinal studies when in-person assessment is not feasible.