Whether you have to claim fundraiser donations depends on who you are and who you give to. The Internal Revenue Service requires both individuals and groups receiving fundraising gifts to claim the money received as income, but the donor does not always claim the gift.
Fundraising for Individuals
When you give money to individuals, you do not claim this gift as a charitable donation on your tax return because no one besides the individual benefits from your gift. This includes political campaign donations, which do not count as charitable gifts.
Fundraising for Groups
Whether you can deduct a fundraising donation to a group depends on the group's status. Gifts to organizations that have a certified non-profit designation of 501(c)3 or other groups that count as charities but lack this designation--typically schools or religious organizations--can be deducted as a charitable contribution and should be claimed. Fundraising gifts to for-profits or other companies don't get you a tax break, and therefore don't need to be claimed.
Reporting Funds to IRS
If you are an individual who received funds from someone, you would claim this money as income on your tax return, using your Form 1040. If you are a certified non-profit, you would use the Form 990's "Statement of Revenue" section to claim your fundraising gifts to the IRS. Whether you're a business or an individual, fundraising gifts count as money in your pocket, which means you need to report it.
If you're planning a fundraiser--whether you're an organization or an individual--check with your community to see if there are limits on the type of activity you can hold, or laws that affect your plan. For example, the state of Massachusetts only allows charities that have existed for two years to hold raffles, and requires them to contact the state's Department of Revenue if they need to hire employees to work the fundraiser. The state of Colorado requires charities to register with the Secretary of State before holding fundraisers and to file a "Notice of Solicitation" with the Secretary of State 15 days before beginning a fundraising campaign.