Background: Crohn's disease (CD) causes transmural ulceration of the gastrointestinal tract (GI), with the terminal ileum and colon being the most commonly affected.

Aim of the Work: to assess the sensitivity & specificity of Intestinal ultrasound In diagnosis of patients with Crohns Disease , assessing activity and possible complications.

Patients and Methods: A Cross sectional study of 30 Patients with Crohns disease from inpatient and outpatient clinic of gastroenterology department of Ain Shams University Hospitals from July to December 2021.

Results: the mean age of patients was 54.3± 7.69 years with range from 38-68 years. Male cases were (70%) while (30%) were females. the mean hemoglobin level was 11.66 ± 1.46 mg/dl. The mean platelets was 267.73±61.94 (K/UL), mean WBCs was 9.94 ± 1.83 (K/UL). the mean serum urea, creatinine and uric acid were 46.43-±10.18, 1.10-±0.25 and 5.30-±0.68 mg/dl respectively. The mean levels of Na and K were normal , the mean liver functions tests were within normal range. the mean CRP was 4.91 ±4.55, the mean ESR at first hour was 21.67 ±4.22 and 2nd hour was 47.43±10.94.

Conclusion: Crohn's disease (CD) is a progressive, inflammatory disease in genetically predisposed individuals , necessitates continuous monitoring with different methods for diagnostic and treatment options. colonoscopy is the gold standard in CD, US, CT and MRI can provide information about the luminal and serous side of the bowel and the peripheral structure. US is repeatable, safe, unlike CT is radiation-free, and unlike MRI is inexpensive, virtually hazard-free, and available without contraindications.