According to the Internal Revenue Service, anyone who has enough taxable income is required to file an income tax return, even senior citizens. Older taxpayers, however, do have a slightly higher threshold for filing.
Publication 501 from the Internal Revenue Service explains that filing requirements vary depending on marital status, age and whether the taxpayer can be claimed as a dependent by another taxpayer. Determining whether a senior citizen needs to file a tax return can be complex. The IRS provides a chart in Publication 575 to assist taxpayers. Self-employment income, subject to its own tax, may require a senior citizen to file even though the income is fairly low. Seniors who are not sure if they have to file a tax return should contact the IRS or a tax professional for help.