Mannatech (MTEX) 8-K/A Changes in Registrant.s Certifying Accountant

Exhibit 16.1

PricewaterhouseCoopers LLP

2001 Ross Avenue, Suite 1800

Dallas TX 75201-2997

Telephone (214) 999  1400

Facsimile (214) 754  7991

May 13, 2005

Securities and Exchange Commission

450 Fifth Street, N.W.

Washington, D.C. 20549

Commissioners:

We have read the statements made by Mannatech, Incorporated (copy attached), which we understand will be filed with the United States Securities and Exchange Commission, pursuant to Item 4.01 of Form 8-K, as part of Mannatech’s Form 8-K/A report dated April 27, 2005. We agree with the statements concerning our Firm in such Form 8-K/A.

Very truly yours,

/s/    PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP