Theory: Theories of the bureaucratic personality by Victor Thompson and Robert Merton hold that personal characteristics of certain bureaucrats make them prefer elaborate rules and regulations, so this study tests such a model. Yet some organizations really do need more rules, so the study also tests a bureaucratic organization model that predicts that characteristics of the organization determine members' preferences for rules. Prominent theories of bureaucracy also suggest that bureaucratic personalities should be more prevalent in public bureaucracies. Hypotheses: Personal characteristics of organizational managers determine their preferences for more rules, so managers higher on alienation and pessimism will perceive a need for more rules. Alternatively, organizational characteristics (such as layers of authority and number of records kept) determine managers' preferences for more rules, so that where there are low levels of such structural characteristics (e.g., few records kept), managers will perceive a need for more rules. Public sector managers should show more of the bureaucratic personality responses than private managers, and prefer more rules. Methods: Correlation and logistic regression analysis is used on data from the National Administrative Studies Project, a mail survey of managers in a wide variety of public and private organizations. Results: Both personal characteristics, such as alienation, and organizational characteristics, such as the number of records kept, show relations to preferences for more rules. Contrary to expectations and to much of the literature, managers in private organizations (mostly business firms) were more likely to prefer more rules than managers in public agencies.