Preliminary Proxy Statement

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Definitive Proxy Statement

Definitive Additional Materials

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*** Exercise Your Right to Vote ***

Important Notice Regarding the Availability of Proxy Materials for the

Stockholder Meeting to Be Held on May 29, 2019

Meeting Information

Meeting Type: Annual Meeting

For holders as of: April 01, 2019

Date: May 29, 2019        Time: 10:00 AM PDT

www.virtualshareholdermeeting.

com/ILMN2019

ILLUMINA, INC.

5200 ILLUMINA WAY

SAN DIEGO, CA 92122

ATTN: JACQUIE ROSS

You are receiving this communication because you hold shares in the above named company.

This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side).

We encourage you to access and review all of the important information contained in the proxy materials before voting.

See the reverse side of this notice to obtain proxy materials and  voting instructions.

How to Access the Proxy Materials

Proxy Materials Available to VIEW or RECEIVE:

1. Notice & Proxy Statement              2. Form 10-K

Have the information that is printed in the box marked by the arrow (located on the following page) and visit: www.proxyvote.com.

1) BY INTERNET:

2) BY TELEPHONE:

3) BY E-MAIL*:

*   If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow (located on the following page) in the subject line.

Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before May 15, 2019 to facilitate timely delivery.

Please Choose One of the Following Voting Methods

Vote In Person: Many stockholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares.

Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow available and follow the instructions.

Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

Voting items

Nominees

Frances Arnold, Ph.D.

Francis A. deSouza

Susan E. Siegel

The Board of Directors recommends you vote FOR proposals 2, 3 and 4.