Purpose: To evaluate long-term disease control and chronic toxicities observed in patients treated with intensity-modulated radiation therapy (IMRT) for clinically localized prostate cancer. Methods/Materials: 302 patients with localized prostate cancer treated with image guided IMRT between 7/2000 and 5/2005 were retrospectively analyzed. Risk groups (low, intermediate, and high) were designated based on NCCN guidelines. Biochemical control was based on the ASTRO (Phoenix) consensus definition. Chronic toxicity was measured both at peak symptoms and at last visit. Toxicity was scored based on CTCAE v.4. Results: The median dose delivered was 75.6 Gy (range 70.2-77.4 Gy) and 35.4% of patients received androgen deprivation therapy (ADT). Patients were followed until death or from 6-138 months (median 91 months) in those alive at last evaluation. Local and distant recurrence rates were 5% and 8.6%, respectively. At 9 years, biochemical control rates was 77.4% for low risk, 69.6% for intermediate risk, and 53.3% for high-risk patients (log rank p= 0.05). On multivariate analysis, T-stage and PSA group were prognostic for biochemical control. At last follow-up, only 0%/0.7% had persistent grade = 3 GI/GU toxicity. High risk group was associated with higher distant metastasis rate (p=0.02) and death from prostate cancer (p=0.0012). Conclusions: This study represents one of the longest experiences with IMRT for prostate cancer. With a median follow-up of 91 months, IMRT resulted in durable biochemical control rates with very low chronic toxicity.