SECURITIES AND EXCHANGE COMMISSION 

Washington, D.C. 20549 

Form 6-K

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934 

For the month of August, 2006

CIBA SPECIALTY CHEMICALS HOLDING INC.

(Exact name of Registrant as specified in its charter)

Klybeckstrasse 141

4002 Basel

Switzerland

(Address of principal executive offices)

     (Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.)

Form 20-F þ  Form 40-F o

     (Indicate by check mark whether by furnishing the information contained in this Form, the Registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2 (b) under the Securities Exchange Act of 1934.)

Yes o   No þ

     (If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2 (b))

CIBA SPECIALTY CHEMICALS HOLDING INC.

On August 17, 2006, Ciba Specialty Chemicals Holding Inc., a stock corporation organized under the laws of Switzerland, issued a News Release regarding its six month (or half year) results 2006. A copy of the News Release is attached as Exhibit 99.1 and incorporated by reference herein.

EXHIBIT LIST

Exhibit	Description
99.1	News Release: Half Year Results 2006, dated August 17, 2006

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

		Ciba Specialty Chemicals Holding Inc.
		(Registrant)
Date August 17, 2006	By	/s/ Oliver Strub	/s/ Daniel Petitpierre
		Oliver Strub Head Corporate Law	Daniel Petitpierre Senior Legal Counsel