How to import contacts from CSV on Mailchimp

beginner 8 min read Updated 2026-03-18

Quick Answer

To import contacts from CSV in Mailchimp, navigate to your audience, click Import Contacts, upload your CSV file, and map the columns to Mailchimp fields. The process typically takes a few minutes to complete depending on file size.

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Prerequisites

Active Mailchimp account
CSV file with contact data properly formatted
Audience/list already created in Mailchimp
Email addresses in valid format

Step-by-Step Instructions

Navigate to your Audience

Log into your Mailchimp account and click on Audience in the main navigation menu. Select the audience where you want to import your contacts, or create a new one by clicking Create Audience.

Make sure you're importing to the correct audience as contacts cannot be easily moved between audiences later.

Access the Import Contacts feature

In your selected audience, click on Add contacts dropdown menu and select Import contacts. This will open the import wizard where you can upload your CSV file.

Upload your CSV file

Click Upload file and select your CSV file from your computer. Mailchimp accepts files up to 10MB in size. Once uploaded, click Continue to proceed to the next step.

Ensure your CSV file has column headers in the first row for easier mapping.

Map CSV columns to Mailchimp fields

Mailchimp will display your CSV columns and ask you to map them to corresponding fields. Map Email Address first (required), then map other columns like First Name, Last Name, and any custom fields. Click Continue when mapping is complete.

You can create new merge tags for custom fields that don't exist in your audience yet.

Configure import settings

Choose whether to Subscribe contacts automatically or keep them Unsubscribed until they opt-in. Select if you want to Update existing contacts or skip duplicates. Review the settings and click Continue.

For compliance, consider importing contacts as unsubscribed and send a re-engagement campaign.

Add tags and review

Optionally add tags to organize these imported contacts. Review the import summary showing total contacts, new contacts, and updates. Verify all settings are correct before proceeding.

Tags help segment your imported contacts for targeted campaigns later.

Complete the import

Click Import to start the process. Mailchimp will show a progress indicator and send you an email notification when the import is complete. You can close the window and check back later for large imports.

Verify imported contacts

Once the import completes, go to your Audience dashboard to verify the contacts were imported correctly. Check the contact count and review a few individual contact profiles to ensure data mapped properly.

Look for any import errors in the notification email and address them promptly.

Common Issues & Troubleshooting

CSV file upload fails or shows formatting errors

Ensure your CSV uses UTF-8 encoding, has proper column headers, and email addresses are in valid format. Remove any special characters or extra commas that might break the CSV structure.

Email addresses are rejected during import

Check that email addresses follow proper format (user@domain.com) and remove any invalid entries. Mailchimp will reject obviously fake emails like test@test.com or emails with invalid domains.

Custom fields don't map correctly

Create the custom merge tags in your audience settings first, then re-import. Ensure column headers in your CSV match the merge tag names exactly.

Import gets stuck or fails to complete

Try splitting large CSV files (over 25,000 contacts) into smaller batches. Clear your browser cache and try again, or wait a few hours if Mailchimp is experiencing high traffic.

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