Questionnaire responses were secured from the senior managements of 103 Canadian firms about their operating styles. The dimensions of top management style studied were risk taking, optimization, orientation, participation, structuring, and coercion. Based on cluster analysis of the data, a number of operating top management styles were identified. Several environmental and contextual variables were employed to study the contextual conditions supportive of each style. Two indices of organizational performance were employed to assess the effectiveness of these styles. One index was based on objective measures of performance, namely, profitability, stability of profitability, and growth rate. The other was based on the management perception of performance relative to rivals. Implications for the design of organizations are drawn.