NOTE: I wrote this post in 2012, so be aware of its age. The information in the post is still accurate.
The question of whether a person can deduct donations to a 501(c)(4) organization comes up periodically. The answer is, no, you can’t deduct those donations as a charitable contribution. Only donations to 501(c)(3) entities are deductible as charitable contributions.
Donations to 501(c)(4) organizations are not deductible as charitable contributions. There are two exceptions: one is for donations to 501(c)(4) volunteer fire companies, and the other is for war veteran organizations (such as the VFW) — those donations ARE deductible. But otherwise, you can’t deduct contributions to a 501(c)(4).
Businesses that make donations to a 501(c)(4) might be able to take a deduction as a business expense, such as an advertising expense, depending on the nature of the donation.
For more tax considerations to think about before making a donation, check out William Perez’s article “Tax Tips for Charitable Giving” at the About.com Tax Planning website.