Sex steroid hormones are essential for a healthy ocular surface and the androgen receptor impairment found in patients with complete androgen insensitivity syndrome (CAIS) has been described to cause meibomian gland dysfunction and functional dry eye for lipid tear film layer instability. However, it has not been reported if the mucous layer is also affected. A 37-year-old CAIS patient with persistent symptoms of dry eye underwent ophthalmological examination and was evaluated for qualitative and quantitative tear function tests and conjunctival cytology. Samples obtained from the conjunctival epithelium were stained for histology and immunohistochemistry and compared with three age-matched female controls. Western blot and relative real-time RT-PCR for MUC1 and MUC5AC were also performed on these samples. Immunohistochemistry, Western blot and relative real-time RT-PCR showed a decrease in the expression of MUC1 and MUC5AC in CAIS. Changes in the tear film mucous layer were accompanied by a reduction in the tear film break up time test. This is the first report describing mucous layer alteration associated with androgen receptor impairment. Decreased mucin levels contribute in explaining the tear film instability in CAIS and should be considered an additional cause of dry eye in sex steroid hormone pathology.