In our study we tried to assess the usefulness of high frequency ultrasound examinations in the diagnostics of right lower quadrant abdominal pain, focusing on the differential diagnosis of appendicitis. Ultrasound examinations were performed on 152 patients aged 1 to 19 with abdominal pain. All the children underwent standard abdominal ultrasound examination with B mode of abdominal parenchymal organs as well as the evaluation of the intestines with the linear transducer of changeable frequency with the possibility of creating sector format. The tissue harmoning imaging (THI), Power and Colour Doppler modes were also applied in the examinations. As a result, 21 (13.8%) of 152 examined patients did not demonstrate any abnormalities in ultrasound examination. In the group the appendix was not visible. In the other 131 (86.2%) patients we observed a number of pathologies such as following: in 96 (73.3%) patients visible appendix, in 8 (6.1%) enlarged mesenteric lymph nodes, in 6 (4.6%) pathological broadening of the distal ileum wall, in 6 (3.2%) pathological broadening of the caecum wall and others. All these symptoms might be treated as indirect symptoms of appendicitis. In conclusion, we would like to state that high frequency ultrasound examination is very useful in the diagnostics of appendicitis.