Objective: To evaluate the validity of the Asthma Control Test (ACT) for assessing clinical asthma control in Chinese patients in primary care settings. Methods: This multicenter study involved 403 asthma patients from 15 primary care settings in China, who had completed the ACT, Asthma Control Questionnaire (ACQ), and spirometry testing. According to the rating of asthma control by asthma specialists in line with the Global Initiative for Asthma 2006 guidelines, patients were divided into uncontrolled, partly controlled, and controlled groups to evaluate the reliability, empirical validity, and screening accuracy of the ACT. The screening accuracy of the ACT and ACQ was analyzed comparatively, and the asthma control levels rated by the patients and the specialists were also compared. Results: The five-item ACT had an internal consistency reliability of 0.861 and a correlation coefficient with the specialists' rating of 0.697. The ACT scores showed significant differences between different levels of FEV(1) percent predieted (F = 37.59; p < 0.0001) and specialists' ratings of asthma control (F = 169.53; p < 0.0001), and also between patients requiring different treatment adjustments (F = 111.33; p < 0.0001). The asthma was controlled for an ACT score of >= 20, partly controlled for scores of 19 and 18, and uncontrolled for a score of <= 17. The ACT showed similar percentages of correctly classified results with ACQ. The patients' self-rated asthma control level was significantly higher than that rated by the specialists (z = 5.93; p < 0.0001). Conclusions: The ACT is reliable, valid, and practicable for asthma control assessment in Chinese patients in the primary care setting.