The situational theory of leadership and the LEAD instruments for determining leadership style are explained, and the application of the situational leadership theory to the process of planning for and implementing organizational change is described. Early studies of leadership style identified two basic leadership styles: the task-oriented autocratic style and the relationship-oriented democratic style. Subsequent research found that most leaders exhibited one of four combinations of task and relationship behaviors. The situational leadership theory holds that the difference between the effectiveness and ineffectiveness of the four leadership styles is the appropriateness of the leader's behavior to the particular situation in which it is used. The task maturity of the individual or group being led must also be accounted for; follower readiness is defined in terms of the capacity to set high but attainable goals, willingness or ability to accept responsibility, and possession of the necessary education or experience for a specific task. A person's leadership style, range, and adaptability can be determined from the LEADSelf and LEADOther questionnaires. By applying the principles of the situational leadership theory and adapting their managerial styles to specific tasks and levels of follower maturity, the authors were successful in implementing 24-hour pharmacokinetic dosing services provided by staff pharmacists with little previous experience in clinical services. The situational leadership model enables a leader to identify a task, set goals, determine the task maturity of the individual or group, select an appropriate leadership style, and modify the style as change occurs. Pharmacy managers can use this model when implementing clinical pharmacy services.