Background: Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by sensitization to allergens. Increased specific IgE to animal dander is commonly found in AD patients, yet a thorough analysis of its clinical significance is lacking. Objectives: To identify the prevalence of AD patients sensitized to animal dander, and evaluate the clinical characteristics of these patients Methods: Of the patients diagnosed with AD at Dermatology Clinic, Severance Hospital, CAP immunoassay was performed to evaluate the sensitization to cat and dog. Patients’ age, sex, allergic comorbidities were obtained from the medical chart. The severity was assessed by EASI scores. Results: The mean age of the patients was 21.72. Those sensitized to cat were found to have a significantly higher total IgE (2371.68 and 1018.46 kU/L, p<0.01) and higher sensitization to Dermatophagoides farinae than those not sensitized (4.67 and 34.73 kU/L, p<0.01). Those sensitized to cat were found to have higher EASI scores than those not sensitized, although the difference was not significant. The number of allergic comorbidities, such as allergic rhinitis and asthma, were found to be higher in those sensitized to cat. Conclusion: Although the sensitization rate of cat is not as high as to housedust mite, it is associated with increased total IgE and increased severity, with higher number of allergic comorbidities. With increasing number of pets, the presence of these sensitizations should also be evaluated.