Here, we report on the prevalence of allergic conjunctivitis and positive skin prick test (SPT) results in relation to respiratory allergic conditions among patients with symptoms of allergies at a respiratory outpatient clinic. A questionnaire survey of symptoms (i.e., asthma-like, rhinitis, and conjunctivitis symptoms) involving 1522 patients was carried out. The responses of 1242 patients indicated that they had allergic conjunctivitis, asthma, rhinitis, or a combination of these conditions, and 869 of these patients underwent SPTs that assessed responses to 40 allergens. Allergic conjunctivitis was found to be very common (40%, 497 out of 1242 patients) among those with symptoms of allergies. Conjunctivitis was slightly more common among women, while rhinitis was more common among men. Patients with both conjunctivitis and rhinitis were more likely to undergo SPTs, and they had a higher rate of positive SPTs. The coexistence of two or more comorbidities increased the risk of having an immunoglobulin E (IgE)-mediated allergy (based on the SPT results) compared to having each of the conditions alone. In conclusion, allergic conjunctivitis can occur either alone or with asthma and/or rhinitis. It is not always accompanied by rhinitis, but the coexistence of these conditions was the strongest indicator of IgE-mediated allergies.