Exhibit 16.1



April 4, 2006
Securities and Exchange Commission
100 F Street, N.E.
Washington, D.C. 20549
Commissioners:

We have read the statements made by NL Industries,  Inc. Retirement Savings Plan
(the  "Plan")  (copy  attached),  which we  understand  will be  filed  with the
Commission,  pursuant to Item 4.01 of Current Report on Form 8-K, as part of the
Plan's Form 8-K dated March 8, 2006. We agree with the statements concerning our
Firm in such Form 8-K.

Very truly yours,

PricewaterhouseCoopers LLP