Diagnosis involves several tests to assess esophageal function and structure. Esophageal manometry is the gold standard, measuring the muscle contractions and sphincter relaxation. Barium swallow X-ray shows a characteristic “bird-beak” narrowing at the lower esophageal sphincter. Upper endoscopy helps rule out other causes like tumors or strictures. Sometimes, CT scans are used to exclude external compression or malignancy. Early and accurate diagnosis is crucial for effective treatment.