To investigate a group of Irish ankylosing spondylitis patients: current prescription practice for TNF blockers and patient response. All patients presenting with ankylosing spondylitis (AS) and treated with TNF-alpha between January 2006 and 2008 in the midwestern region of Ireland were studied. Response was evaluated using Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and CRP results at 6 months. A total of 47 AS patients (32 men: 15 women, mean age 37.7 years, median disease duration 20 years, 80% HLA B27 positive) were identified; 66% were on disease-modifying anti-rheumatic drugs (DMARDs) concomitantly. All patients satisfied BSR/ASAS disease severity criteria for TNF-alpha at baseline, and mean BASDAI was 6.2, BASFI 6.9, and CRP 27.5 mg/L. At 6 months, these had reduced to a mean BASDAI of 3.8, BASFI 4.6, and CRP of 8.9 mg/L. Patients with advanced AS (disease duration >10 years, mean BASFI 7.5) responded at least as well. No allergies or serious side effects were encountered, and one patient successfully switched TNF agent due to secondary failure. Initial good responses at 6 months were seen to be maintained in sub-group analysis at 12 months. Disease severity in patients gaining access to treatment for active AS with TNF blockers in Ireland is very high. Patients mainly satisfy international guidelines for the use of biologics (BSR, EULAR) with some minor exceptions. High disease activity and long disease duration may predict better treatment response. Response rates were good and treatment was well tolerated, and no differences in response were noted between the 3 agents employed.