A 1-year, open-label extension of a 12-week, double-blind clinical trial was conducted to evaluate the long-term safety and efficacy of once-daily therapy with triamcinolone acetonide nasal aerosol (110, 220, or 440 micrograms) in 93 patients with perennial allergic rhinitis. All three doses of triamcinolone acetonide were associated with sustained improvement in allergic rhinitis symptoms over the course of 1 year, as evidenced by physicians' and patients' global evaluations, ratings of the nasal environment (appearance and color of the nasal mucosa, as well as the quality of nasal secretions), nasal eosinophil counts, and requirement for escape medication. Among patients who reported adverse clinical experiences, most were considered unrelated or remotely related to therapy. Few patients experienced nasal irritation or throat discomfort, and no serious adverse experiences were attributed to treatment. Among 6 patients who withdrew from the study because of adverse experiences, a possible drug relationship was cited in 2 individuals (1 with headache and 1 with nasal blood) and a remote relationship in 1 (with acne). No clinically meaningful changes in vital signs, physical examinations, or laboratory values were noted, and mean serum cortisol levels were not suppressed during long-term treatment. These findings demonstrate that both safety and efficacy are maintained during long-term once-daily therapy with triamcinolone acetonide nasal aerosol in patients with perennial allergic rhinitis.