In the face of an overwhelmingly large and growing medical literature, providers often turn to clinical practice guidelines to inform the decisions they make with patients. By systematically appraising the evidence and providing transparent recommendations for practice, guidelines have the potential to improve both bedside decision-making and health policy. This potential has not been fully realized because most guidelines lack transparency, are tainted by conflicts of interest, or fail to employ rigorous methods to appraise the evidence. To address the shortcomings of past guidelines, the Institute of Medicine (IOM) published recommendations for trustworthy guidelines, effectively setting the "gold standard" for what constitutes a high-quality guideline. Along with many other groups that develop guidelines, the American Thoracic Society (ATS) is rapidly evolving processes for development and implementation to meet many of the IOM standards. This Pulmonary Perspective describes the rapidly changing landscape of clinical practice guidelines, the role of the ATS in this landscape, and the activities the ATS is engaged in to ensure that the guidelines it produces are of the highest quality with the broadest impact.