You may claim your tax back but your payment from Social Welfare is also taxable. Your tax refund is based on tax paid in the current year, so if you haven't paid any tax to the date you were made redundant you will not be due a tax refund. Download Form P50 from revenue website and forwarded completed form together with your P45 to your local tax office. They will advise you of how much (if any) tax is due to you.