Can you claim advertising costs for affiliate websites?

Yes—if your affiliate websites are run as a business, you can generally deduct ordinary and necessary advertising costs used to drive traffic, promote your site, or generate affiliate revenue. Common examples include paid search ads, social media ads, display ads, sponsored posts, email marketing tools used for campaigns, creative/design for ads, and payments to influencers or freelancers for promotion.

Key conditions:

• The expense must be business-related, not personal.
• You should keep invoices, receipts, ad platform statements, and notes showing the campaign/business purpose.
• If an expense has both personal and business use, deduct only the business portion.
• Startup advertising before the site is actively operating may be treated differently from ongoing ad expenses.
• If you receive free products, commissions, or other compensation connected to affiliate promotion, those may have tax reporting implications too.

For U.S. taxes, these costs are commonly reported as advertising expenses for a sole proprietor on Schedule C, but the exact treatment depends on your business structure and country/state rules. If the amounts are significant or you are unsure whether the site is a hobby or a business, check with a tax professional before filing.