Ornamental plants (OPs) can lead to immediate-type sensitization and even asthma and rhinitis symptoms in some cases. This study aimed to evaluate sensitization to OPs in patients with asthma and/or allergic rhinitis and to determine the factors affecting the rate of sensitization to OPs. A total of 150 patients with asthma and/or allergic rhinitis and 20 healthy controls were enrolled in the study. Demographics and disease characteristics were recorded. Skin-prick tests were performed with a standardized inhalant allergen panel. Skin tests by "prick-to-prick" method with the leaves of 15 Ops, which are known to lead to allergenic sensitization, were performed. Skin tests with OPs were positive in 80 patients (47.1%). There was no significant difference between OP sensitized and nonsensitized patients in terms of gender, age, number of exposed OPs, and duration of exposure. Skin test positivity rate for OPs was significantly high in atopic subjects, patients with allergic rhinitis, food sensitivity, and indoor OP exposure, but not in patients with pollen and latex allergy. Most sensitizing OPs were Yucca elephantipes (52.5%), Dieffenbachia picta (50.8%), and Euphorbia pulcherrima (47.5%). There was significant correlation between having Saintpaulia ionantha, Croton, Pelargonium, Y. elephantipes, and positive skin test to these plants. Sensitivity to OPs was significantly higher in atopic subjects and patients with allergic rhinitis, food allergy, and indoor OP exposure. Furthermore, atopy and food sensitivity were found as risk factors for developing sensitization to indoor plants. Additional trials on the relationship between sensitization to OPs and allergic symptoms are needed.