BACKGROUND Allergy to hydrolyzed wheat protein in facial soap has become a major social issue in Japan. It has been reported that the most frequent early symptoms of allergy to hydrolyzed wheat protein in soap are allergic conjunctivitis and rhinitis, while wheat-dependent exercise-induced anaphylaxis can be induced by long-term use. OBJECTIVE We evaluated the relation between tear fluid levels of specific IgE for wheat and the features of allergic conjunctivitis. METHODS A prospective, non-randomized, cross-sectional study was conducted in 103 patients with moderate to severe allergic conjunctivitis (allergic group) and 20 age- and sex-matched healthy control subjects (control group). Specific IgE for wheat was measured in tear fluid with an immunochromatography assay, and a skin prick test (SPT) was also performed. Symptoms (sneezing, rhinorrhea, nasal obstruction, ocular itching, and lacrimation) were assessed in each subject along with the activities of daily living (ADL) score and the total ocular symptom score for allergic conjunctivitis. A severity score (0, 1, 2, or 3) was assigned for various changes of the palpebral and bulbar conjunctiva, as well as for limbal and corneal lesions associated with allergic conjunctivitis. RESULTS The IgE positive rate and specific IgE score were both higher in the allergic group than in the control group (71.8% versus 40.0% and 1.9 ± 0.7 versus 1.4 ± 0.5). A positive SPT for wheat was also more frequent in the allergic group than in the control group (6.8% versus 0.0%). Within the allergic group, patients with a positive SPT had higher specific IgE scores than patients with a negative SPT (3.3 ± 0.5 versus 1.8 ± 0.6, p < 0.001). In the allergic group, the wheat IgE level in tear fluid was correlated with the severity of allergic conjunctivitis symptoms, including ocular itching (r = 0.665), tearing (r = 0.672), and the total ocular symptom score (r = 0.204). Wheat IgE in tear fluid was also correlated with the severity of rhinitis symptoms, including sneezing (r = 0.610), nose blowing (r = 0.640), and nasal obstruction (r = 0.677). Furthermore, the tear fluid wheat IgE score was correlated with five objective features of allergic conjunctivitis (p < 0.05). CONCLUSIONS These results suggest that wheat allergy may be involved in the development of allergic conjunctivitis.