The American College of Physicians (ACP) developed this guideline to provide clinical recommendations on the appropriate use of point-of-care ultrasonography (POCUS) in patients with acute dyspnea in emergency department (ED) or inpatient settings to improve the diagnostic, treatment, and health outcomes of those with suspected congestive heart failure, pneumonia, pulmonary embolism, pleural effusion, or pneumothorax. The ACP Clinical Guidelines Committee based this guideline on a systematic review on the benefits, harms, and diagnostic test accuracy of POCUS; patient values and preferences; and costs of POCUS. The systematic review evaluated health outcomes, diagnostic timeliness, treatment decisions, and test accuracy. The critical health, diagnostic, and treatment outcomes evaluated were in-hospital mortality, time to diagnosis, and time to treatment. The important outcomes evaluated were intensive care unit admissions, correctness of diagnosis, disease-specific outcomes, hospital readmissions, length of hospital stay, and quality of life. The critical test accuracy outcomes included false-positive results for suspected pneumonia, pneumothorax, and pulmonary embolism and false-negative results for suspected congestive heart failure, pneumonia, pneumothorax, and pulmonary embolism. Important test accuracy outcomes included false-positive results for suspected congestive heart failure and false-negative and false-positive results for suspected pleural effusion. This guideline was developed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) The target audience is all clinicians, and the target patient population is adult patients with acute dyspnea in ED or inpatient settings.ACP suggests that clinicians may use point-of-care ultrasonography in addition to the standard diagnostic pathway when there is diagnostic uncertainty in patients with acute dyspnea in emergency department or inpatient settings (conditional recommendation; low-certainty evidence).