Title 26 — Internal Revenue
- Chapter I Internal Revenue Service, Department of the Treasury
- Subchapter A Income Tax
- Part 1 – Income Taxes 41 pending
- Part 2 – Maritime Construction Reserve Fund
- Part 3 – Capital Construction Fund
- Part 4 – Temporary Income Tax Regulations Under Section 954 of the Internal Revenue Code
- Part 5 – Temporary Income Tax Regulations Under the Revenue Act of 1978
- Part 5c – Temporary Income Tax Regulations Under the Economic Recovery Tax Act of 1981
- Part 5e – Temporary Income Tax Regulations, Travel Expenses of Members of Congress
- Part 5f – Temporary Income Tax Regulations Under the Tax Equity and Fiscal Responsibility Act of 1982
- Part 6a – Temporary Regulations Under Title II of the Omnibus Reconciliation Act of 1980
- Part 7 – Temporary Income Tax Regulations Under the Tax Reform Act of 1976
- Part 8 – Temporary Income Tax Regulations Under Section 3 of the Act of October 26, 1974 (Pub. L. 93-483)
- Part 9 – Temporary Income Tax Regulations Under the Tax Reduction Act of 1975
- Part 11 – Temporary Income Tax Regulations Under the Employee Retirement Income Security Act of 1974
- Part 12 – Temporary Income Tax Regulations Under the Revenue Act of 1971
- Part 13 – Temporary Income Tax Regulations Under the Tax Reform Act of 1969
- Part 15 – Temporary Income Tax Regulations Relating to Exploration Expenditures in the Case of Mining
- Part 15a – Temporary Income Tax Regulations Under the Installment Sales Revision Act
- Part 16A – Temporary Income Tax Regulations Relating to the Partial Exclusion for Certain Conservation Cost-Sharing Payments
- Part 18 – Temporary Income Tax Regulations Under the Subchapter S Revision Act of 1982
- Subchapter B Estate and Gift Taxes
- Part 20 – Estate Tax; Estates of Decedents Dying After August 16, 1954
- Part 22 – Temporary Estate Tax Regulations Under the Economic Recovery Tax Act of 1981
- Part 25 – Gift Tax; Gifts Made After December 31, 1954
- Part 26 – Generation-Skipping Transfer Tax Regulations Under the Tax Reform Act of 1986
- Part 28 – Imposition of Tax on Gifts and Bequests from Covered Expatriates
- Subchapter C Employment Taxes and Collection of Income Tax at Source
- Part 31 – Employment Taxes and Collection of Income Tax at Source 2 pending
- Part 32 – Temporary Employment Tax Regulations Under the Act of December 29, 1981 (Pub. L. 97-123)
- Part 35 – Employment Tax and Collection of Income Tax at Source Regulations Under the Tax Equity and Fiscal Responsibility Act of 1982
- Part 35a – Temporary Employment Tax Regulations Under the Interest and Dividend Tax Compliance Act of 1983
- Part 36 – Contract Coverage of Employees of Foreign Subsidiaries
- Subchapter D Miscellaneous Excise Taxes
- Part 40 – Excise Tax Procedural Regulations 1 pending
- Part 41 – Excise Tax on Use of Certain Highway Motor Vehicles
- Part 43 – Excise Tax on Transportation by Water
- Part 44 – Taxes on Wagering; Effective January 1, 1955
- Part 46 – Excise Tax on Certain Insurance Policies, Self-Insured Health Plans, and Obligations Not in Registered Form
- Part 47 – Designated Drugs Excise Tax Regulations
- Part 48 – Manufacturers and Retailers Excise Taxes 4 pending
- Part 49 – Facilities and Services Excise Taxes 1 pending
- Part 50 – Regulations Relating to the Tax Imposed with Respect to Certain Hydraulic Mining
- Part 51 – Branded Prescription Drug Fee 1 pending
- Part 52 – Environmental Taxes
- Part 53 – Foundation and Similar Excise Taxes
- Part 54 – Pension Excise Taxes 2 pending
- Part 55 – Excise Tax on Real Estate Investment Trusts and Regulated Investment Companies
- Part 56 – Public Charity Excise Taxes
- Part 57 – Health Insurance Providers Fee
- Part 58 – Stock Repurchase Excise Tax
- Part 141 – Temporary Excise Tax Regulations Under the Employee Retirement Income Security Act of 1974
- Part 143 – Temporary Excise Tax Regulations Under the Tax Reform Act of 1969
- Part 145 – Temporary Excise Tax Regulations Under the Highway Revenue Act of 1982 (Pub. L. 97-424)
- Part 156 – Excise Tax on Greenmail
- Part 157 – Excise Tax on Structured Settlement Factoring Transactions
- Subchapter F Procedure and Administration
- Part 300 – User Fees 4 pending
- Part 301 – Procedure and Administration 6 pending
- Part 302 – Taxes Under the International Claims Settlement Act, as Amended August 9, 1955
- Part 303 – Taxes Under the Trading with the Enemy Act
- Part 305 – Temporary Procedural and Administrative Tax Regulations Under the Indian Tribal Governmental Tax Status Act of 1982
- Part 400 – Temporary Regulations Under the Federal Tax Lien Act of 1966
- Part 403 – Disposition of Seized Personal Property
- Part 404 – Temporary Regulations on Procedure and Administration Under the Tax Reform Act of 1976
- Part 420 – Temporary Regulations on Procedure and Administration Under the Employee Retirement Income Security Act of 1974
- Subchapter G Regulations Under Tax Conventions
- Subchapter H Internal Revenue Practice
- Part 601 – Statement of Procedural Rules
- Part 602 – OMB Control Numbers Under the Paperwork Reduction Act
- Part 701 – Presidential Election Campaign Fund
- Part 702 – Presidential Primary Matching Payment Account
- Part 801 – Balanced System for Measuring Organizational and Employee Performance Within the Internal Revenue Service
- Subchapter A Income Tax