PURPOSE: To evaluate the safety and efficacy of intralesional triamcinolone acetonide (TA) injection in primary and recurrent chalazia. DESIGN: Retrospective, interventional, consecutive case series. PARTICIPANTS: One hundred forty-seven patients with primary or recurrent chalazia (155 cases) treated at the oculoplastic clinic at the Jules Stein Eye Institute between January 1, 2000, and December 31, 2003. METHODS: Patients received an intralesional injection of 0.1 to 0.2 ml TA (40 mg/ml). Data regarding lesion size, including digital color photography, lesion regression or recurrence, and complete ophthalmic examination, were recorded at the time of injection and at different intervals until resolution or surgical excision. Success was defined as at least an 80% decrease in size with no recurrence. If the lesion recurred or regression was minimal (<50%), further injections were given as needed. Patients who declined injection or who did not respond to 2 to 3 injections were referred for surgical excision and drainage. MAIN OUTCOME MEASURES: Lesion size, clinical resolution, time to resolution, recurrence, and complications. RESULTS: Most of the patients received 1 injection (93 patients; 60%) or 2 injections (31 patients; 20%) with resolution of the lesion (more than 80% decrease in size), with an average time to resolution of 2.5 weeks. Patients who did not respond to 2 injections were more likely to fail treatment (minimal or no regression), to respond to further injections, or to undergo surgical excision and drainage (P = 0.0001, chi-square test). Patients with blepharitis required more injections to resolution (2+/-1.3 vs. 1.4+/-1; P = 0.05, independent samples t test). Intraocular pressure and visual acuity remained stable after treatment. No complications, such as visual loss, subcutaneous fat atrophy, or skin depigmentation changes, were noted with steroids injections; assuming a complication rate of 2%, our power was adequate to rule out these complications. CONCLUSIONS: Intralesional TA injection in primary and recurrent chalazia is effective in achieving lesion regression. Most cases resolve with an average of 1 to 2 injections. Chalazia that fail to respond to 2 or 3 injections are more likely to benefit from surgical excision. It may be considered as a first treatment in cases where diagnosis is straightforward.