AIM: To investigate the clinical features of adult patients with ocular toxocariasis (OT) in north China and to diagnose adults OT patients in early stage. METHODS: Clinical data of 24 adults with OT were retrospectively analyzed. Slit lamp photographs and fundus photographs and other imaging examinations of all the patients were reviewed. A questionnaire concerning the pet ownership and place of residence was completed to investigate the possible infection origin. Descriptive statistical analyses were performed on the demographic data, clinical features, funduscopic findings and ELISA results. RESULTS: Among the 24 patients diagnosed with OT by Toxocara IgG antibody in intraocular fluid, 16 (66.7%) eyes were right eye. The onset age of 12 eyes (50.0%) was between 30 and 40 years old, and 21 (87.5%) eyes were of peripheral granuloma type. The most common sign was vitreous opacity. Granulomas were detected in all the eyes, and 20 (83.3%) patients resided in rural area. In 4 patients, the concentration of anti-Toxocara antibody both in anterior humor and in vitreous humor were detected, and the results showed the concentration in vitreous humor was much higher than aqueous humor. CONCLUSION: Our study analyzes the clinical manifestation of OT in adults, which may have been under-recognized before. Eye side, residence, and detection of granuloma may help us in diagnosis of OT in patients with monocular vitreous opacity. For adult patients with presumed OT, negative results of anti-Toxocara antibody in anterior humor cannot rule out the possibility of OT, further detection of vitreous humor is suggested for final diagnosis.