Background: Although clinical trials documented omalizumab's efficacy in U.S. patients with chronic idiopathic urticaria (CIU), the real-world evidence on its long-term effectiveness is lacking. Objective: To assess omalizumab use and the long-term response in a large sample of U.S. real-world patients. Methods: Patients with CIU and ≥ 12 years old who were initiated on omalizumab (index date) and with ≥ 6 months of postindex data were identified in an electronic medical record system (2007-2018). Omalizumab use was described. Provider assessments of disease control and course, and patient-reported symptoms were compared at 6-month intervals postindex versus baseline in the patients with values available at both time points. Results: A total of 1096 patients (mean age, 44.1 years; 74.7% women) were followed up for a mean of 19 months postindex. Patients, predominantly initiated on a 300-mg dose, received a mean of 15 omalizumab administrations and were treated continuously for a mean of 14.2 months. At 6 months postindex versus baseline, the patients (n = 708) were more likely to be well controlled (odds ratio [OR] 31.68 [95% confidence interval {CI}, 17.20-58.36]) with an improved disease course (OR 15.73 [95% CI, 11.33-21.85]). Moreover, the patients (n = 373) were less likely to report itching (OR 0.39 [95% CI, 0.21-0.76]), rash (OR 0.59 [95% CI, 0.45-0.78]), and swelling (OR 0.46 [95% CI, 0.36-0.59]). Benefits associated with omalizumab treatment were sustained through month 24 and beyond. Conclusion: This real-world study showed that the patients who received a mean of 15 omalizumab administrations over a mean of 14.2 months experienced, starting at 6 and through 24 months after omalizumab initiation and beyond, improved CIU control, course, and symptoms.