This study aims to explore how the transformational leadership (consisting of three factors"charisma, individualized consideration, and intellectual stimulation) and the organizational culture (typified by developmental, rational, consensual, and hierarchical culture) are related to the organizational effectiveness (consisting of job satisfaction, organizational commitment, and intention to leave a job) of dental clinics. We found the following empirical results through a survey of 378 persons who work in dental clinics. Firstly, the respondents acknowledged charismatic leadership as the typical type of leadership ; as for organizational culture, a culture of consensus is recognized as the representative type. Secondly, transformational leadership has different effects according to the type of organizational culture: a positive influence in developmental and rational cultures, but a negative influence in consensual and hierarchical cultures. Thirdly, developmental culture has proven to be the most suitable for increasing job satisfaction and organizational commitment. The developmental, rational, and consensual cultures have all contributed to reducing intention to leave among clinic staff, whereas in the hierarchical culture, intention has been elevated. Fourthly, transformational leadership has a positive effect on the job satisfaction and organizational commitment; the intent to leave has been lessened under individualized consideration and charismatic leadership, but has been increased under leadership of intellectual stimulation. Fifthly, it is consideration and charisma that help to increase organizational effectiveness. These influences will become more effective through a developmental culture. Based on the above empirical results, we propose practical measures to improve the organizational effectiveness of clinics, in particular dental clinics. In order to build developmental culture, the doctor (manager) should produce an atmosphere in the clinic in which staff members are able to create and jointly own ideas and then promote awareness of staff participation. Additionally, in order to bring leadership of charisma and consideration into full play, the doctor should shape a relationship of mutual trust mainly by recognizing and praising the work of clinic staff. Finally, the doctor needs to acknowledge that organizational effectiveness can be significantly improved by increasing the transparency of the business.