The outcomes of patients with elderly onset (EO) inflammatory bowel disease (IBD) treated with anti-tumor necrosis factor (TNF) remains uncertain. The present study evaluated the efficacy and safety of anti-TNF treatment for bio-naïve EO-IBD. Elderly patients were defined as those 60 years and older, and further divided into those with EO (Elderly-EO) and those with non-elderly onset (Elderly-NEO). A total of 432 bio-naïve patients were enrolled in this multicenter observational study, comprising 55 with Elderly-EO (12.7%), 25 with Elderly-NEO (5.8%), and 352 under age 60 (Non-elderly, 81.5%). After 52 weeks of anti-TNF treatment, clinical and steroid-free remission rates were significantly lower in Elderly-EO than in Non-elderly (37.7% and 60.8%; P = 0.001, and 35.9% and 57.8%; P = 0.003, respectively), and comparable between Elderly-NEO and Non-elderly. Multivariate analysis revealed that elderly onset was a significant factor for both clinical remission (OR, 0.49, 95% CI 0.25–0.96) and steroid-free remission (OR, 0.51, 95% CI 0.26–0.99) after 52 weeks of anti-TNF treatment. The rate of cumulative severe adverse events was significantly higher in Elderly-EO than in Non-elderly (P = 0.007), and comparable between Elderly-NEO and Non-elderly. In conclusion, anti-TNF treatment for bio-naïve EO-IBD may be less effective and raise safety concerns.