Acute appendicits is the most common surgical disease of acute abdomen, But the diagnosis of acuteappendicitis is often difficult, and not in frequently, operation for appendicitis is performed only to find anormal appendix, Various radiological examinations have been proposed to improve diagnostic accuracy of appendicitis. The purpose of this study was to improve the diagnostic accuracy of appendicits, and to declinenegative exploration. High resolution real time ultlrasonographical examination using graded compression was performed in 57 consecutive patients who were clinically suspected of appendicitis. Authors analised ultrasonographical, surgical, and clinical follows up findings. The results were are follows: 1. Ultrasonographical finding of acute appendicits was visualization of appendix as a tubular structure with onebline end, or target phenomenon. 2. Hypoecoic area over the appendix was thought to be a sing of periappendicealabscess. 3. The sensitivity of US diagnosis of acute appendicitis in this study was 92.8% with a specificity of93.1%. The overall accuracy was 93.0%. 4. In control group of 50 individuals,the abnormal appendix was notvisualized. 5. In cases of clinically suspected appendicitis, the US evalaution with graded compression techniqueis very accurate and effective examination.