What's New with Illinois Business Registration
Illinois Department of Revenue Publication FY 2004-22 What's New with Illinois Business Registration, Informational Bulletin is to: Tax Practitioners. Effective immediately, complete Form REG-1, Illinois Business registration Application, when registering a business with us. Please do not use Form NUC-1 or any other registration forms you may have previously used. Completing Form REG-1 is the initial step in the registration process for most taxes and fees administered by the Illinois Department of Revenue (IDOR).