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~~April, ~~2005~~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 x

Form 40-F

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

Yes

No x

(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 18~~April 27, ~~2005~~2006, Ciba Specialty Chemicals Holding Inc., a stock corporation, ~~(the~~ ~~"Company")~~ issued a News Release regarding its ~~half~~three ~~year~~month (or first ~~six months~~quarter) ~~results~~ ~~of 2005 and a News Release regarding its appointment of Brendan Cummins~~results ~~to the newly-created position of Chief Operating Officer of the Company~~2006. A A copy of ~~the~~this ~~earnings~~ News Release is attached hereto as Exhibit 99.1 and aincorporated ~~copy of the Chief Operating Officer News Release is attached hereto as Exhibit 99.2, both of which are incorporated~~ by reference herein.

EXHIBIT INDEX

Exhibit	Description
99.1	News Release: ~~Half~~Three ~~Year~~Month Results ~~2005~~2006, dated ~~August~~April 1827, ~~2005~~2006
99.2	News Release: Ciba Specialty Chemicals Appoints Chief Operating Officer, dated August 18, 2005

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 18, 2005	By /s/ Oliver Strub	/s/ Max Dettwiler
Date May 4, 2006	By	/s/ Oliver Strub	/s/ Max Dettwiler
	~~Oliver Strub~~	~~Max~~Oliver ~~Dettwiler~~Strub	Max Dettwiler
	~~Head Corporate Law~~	Head, ~~Taxes,~~ Corporate Law ~~& Insurance~~	Head Taxes,Corporate
			Law & Insurance

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