AIM: To determine the clinical features of the dacryoadenitis subtype of idiopathic orbital inflammatory pseudotumor and its relationship with paranasal sinusitis. METHODS: A retrospective analysis of 46 patients who received surgical treatment at the Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University for the dacryoadenitis subtype of idiopathic orbital inflammatory pseudotumor from October 2010 to December 2012. Each patient underwent magnetic resonance imaging (MRI) of the orbits and the 4 paranasal sinuses. Disease status and the level of serum immunoglobulin G4 (IgG4) was measured before and 6mo after surgery. RESULTS: The initial clinical feature of the idiopathic dacryoadenitis type of orbital inflammatory pseudotumor was redness or swelling of the eyelids. Masses were palpated in the area of the lacrimal gland in some patients. Of the 46 patients, 16 also suffered from sinusitis (34.8%), with 14 cases of ethmoid sinusitis, 8 cases of maxillary sinusitis, 9 cases of sphenoid sinusitis, and 8 cases of frontal sinusitis. Of the 16 patients with sinusitis, 4 patients had a medical history of rhinitis (range: 10mo to 15y previously), 10 patients had occasional nasal congestion, and 2 patients had no nasal congestion. Thirteen of the 46 patients had elevated serum IgG4 levels. Nine of these 13 patients had MRI signs of sinusitis. All patients (n=46) received oral glucocorticoid treatment for approximately 3mo after surgery. No sign of recurrence was found in the orbital MRI 6mo after surgery. Of the 16 patients with sinusitis, 9 cases of elevated serum IgG4 levels improved after treatment with decreased serum IgG4 level and 7 cases of normal serum IgG4 levels remained unchanged. CONCLUSION: Some patients with the dacryoadenitis subtype of idiopathic orbital inflammatory pseudotumor may also suffer from paranasal sinusitis. The incidence of paranasal sinusitis was much higher in patients with IgG4-elevated dacryoadenitis subtype orbital inflammatory pseudotumor than in those with normal IgG4 levels. Dacryoadenitis subtype orbital inflammatory pseudotumor and paranasal sinusitis may both the clinical manifestations of IgG4-related disease involved in different locations.