Pleural effusion is a respiratory disorder marked by abnormal fluid accumulation in the pleural cavity that frequently triggers Dyspnea and anxiety, particularly in emergency settings. Progressive Muscle Relaxation (PMR) is a non-pharmacological, evidence-based nursing intervention recommended to relieve muscle tension, reduce anxiety, and improve breathing pattern. This case study aimed to describe nursing care with the application of PMR therapy on Dyspnea and anxiety reduction in a pleural effusion patient in the Emergency Room. The research design used a nursing care approach (assessing, diagnosing, planning, implementing, evaluating) for a patient. Data were collected through interviews, physical examination, documentation, and observation before and after the intervention. The patient had Dyspnea for one month, worsening with coughing, mild activity, and a supine position, accompanied by restlessness and worry, so that there are several nursing diagnoses, for example activity intolerance, ineffective airway clearance, ineffective breathing pattern, and anxiety. PMR therapy was administered once for 10–20 minutes. After the intervention, respiratory rate decreased from 28 to 24 breaths per minute, oxygen saturation improved from 92% to 96%, and the anxiety score decreased from 24 to 20, with the patient showing a calmer affect and able to follow the relaxation instructions independently. These findings confirm that PMR therapy is an effective, safe, low-cost, and easily applicable evidence-based nursing intervention for improving breathing pattern and reducing anxiety in pleural effusion patients in emergency nursing care.