This study investigates the effects of environmental uncertainty, organizational size, and tolerance of ambiguity of managers on the perceived usefulness of information characteristics of management accounting systems (MAS). An overall measure of usefulness based on the four non-conventional MAS information characteristics of scope, timeliness, level of aggregation, and information for integration were selected based on previous MAS studies (Chenhall and Morris, 1986, The Accounting Review 61, 16-35). Tolerance of ambiguity was introduced as a moderator between environment and information usefulness because information is an important individual resource which makes individuals value information differently depending on the context. Size was included as a surrogate for organizational complexity to further test the strength of the person-environment interaction on information usefulness. The usefulness of MAS information is seen to be affected by interaction patterns between the individual, organizational and environmental levels. Data from 64 managers of New Zealand manufacturing companies suggests that managers of large firms with high tolerance of ambiguity perceive non-conventional MAS information to be most useful when the environment is uncertain.