Given a group composed of N individuals and given a von Neumann-Morgenstern utility function for each individual in the group, how can these be aggregated to obtain a group von Neumann-Morgenstern utility function. The implications of a set of axioms, analogous to Arrow's, using individual cardinal utilities--rather than Arrow's ordinal rankings--are investigated. The result is a group cardinal utility function which explicitly requires interpersonal comparison of preference. Suggestions for who should make these comparisons and how they might be done are given