KRONOS WORLDWIDE INC — Director's Dealing 2007

May 21, 2007

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: KRONOS WORLDWIDE INC (KRO)
CIK: 0001257640
Period of Report: 2007-05-17

Reporting Person: SIMMONS HAROLD C (Director, Chairman of the Board & CEO, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2007-05-17	Common Stock $0.01 par value	A	500	—	Acquired	5755	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock $0.01 value	28995021	Indirect
Common Stock $0.01 value	17516132	Indirect
Common Stock $0.01 value	5203	Indirect
Common Stock $0.01 value	36356	Indirect

Footnotes

F1: Shares issued for no cash consideration to nonemployee directors under the Kronos Worldwide, Inc. 2003 Long-Term Incentive
Plan.

F2: Directly held by Valhi, Inc. See the Additional Information filed as Exhibit 99 to this statement for a description of the
relationships among the persons joining in this filing.

F3: Directly held by NL Industries, Inc. See the Additional Information filed as Exhibit 99 to this statement for a description
of the relationships among the persons joining in this filing.

F4: Directly held by TIMET Finance Management Company. See the Additional Information filed as Exhibit 99 to this statement for
a description of the relationships among the persons joining in this filing.

F5: Directly held by the Reporting Person's spouse. The Reporting Person disclaims beneficiary ownership of these shares.