This practice note discusses the filing requirements for Internal Revenue Service (IRS) Form 990, Return of Organization Exempt from Income Tax. It provides guidance for completing, filing, and amending the form and its accompanying schedules. Tax-exempt organizations, nonexempt charitable trusts, and I.R.C. Section 527 political organizations file Form 990 to provide the IRS with the information necessary to comply with I.R.C. Section 6033(e), which imposes reporting and notice requirements on certain tax-exempt organizations. Form 990 is a public document that is made available by filing organizations, the IRS, and others. It is the key transparency tool relied on by the public, state regulators, the media, researchers, and policymakers to obtain information about the tax-exempt sector and individual organizations.