SECURITIES ANDTable EXCHANGEof COMMISSIONContents

~~Washington, D.C.~~SECURITIES ~~20549~~AND EXCHANGE COMMISSION

~~Form~~Washington, D.C. 20549 ~~6-K~~

~~Report~~FORM of6-K ~~Foreign Issuer~~

~~Pursuant~~Report of Foreign Issuer Pursuant to Rule 13a-16 or 15d-16 of the Securities Exchange Act of 1934

For the ~~Securities~~ ~~Exchange~~month ~~Act~~ of ~~1934~~August 2005

~~For~~CIBA ~~the~~SPECIALTY CHEMICALS ~~month~~HOLDING ~~of May, 2005~~INC.

~~CIBA~~(Exact name of Registrant ~~SPECIALTY~~as ~~CHEMICALS~~specified ~~HOLDING~~in ~~INC.~~its charter)

~~(Exact~~Klybeckstrasse 141 ~~name~~4002 Basel Switzerland (Address of ~~Registrant~~principal asexecutive ~~specified in its charter~~offices)

~~Klybeckstrasse~~Indicate by check mark ~~141~~whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

~~4002 Basel~~Form 20-F þ Form 40 F o

~~Switzerland~~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.

~~(Address of~~Yes ~~principal~~o ~~executive~~No ~~offices)~~þ

(~~Indicate by~~If ~~check~~“Yes” ~~mark~~is ~~whether~~marked, indicate below the ~~registrant files or will~~ file ~~annual~~number ~~reports~~assigned ~~under cover~~to ofthe ~~Form~~registrant ~~20-F~~in orconnection ~~Form 40~~with Rule 12g3-F.2(b))

~~Form~~TABLE ~~20-F~~OF ~~x Form 40-F __~~CONTENTS

~~(Indicate by~~SIGNATURES ~~check~~EXHIBIT ~~mark~~INDEX ~~whether~~Exhibit ~~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~~99.)1

YesTable ___of No xContents

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

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

On May 17, 2005, Ciba Specialty Chemicals Holding Inc. ("Ciba"), a stock corporation, received confirmation that the filing of the notarial deed (including the Amended Articles of Association) had been entered into the diary of the commercial register in Basel, Switzerland. As such, the capital reduction of the par value of Ciba's shares from CHF 3 per share to CHF 1 per share had been consummated and the associated payment to the shareholders of CHF 2 per share will be paid on May 18, 2005 (see attached notice). A report of the statutory auditors prepared by Ernst & Young Ltd. was also filed with the commercial register. A copy of English translations of the Amended Articles of Association, Ernst & Young Ltd. report, notice to the Swiss Exchange and a copy of the Swiss commercial register are attached hereto as Exhibits 3.1, 99.1, 99.2 and 99.3, respectively, and incorporated by reference herein.


Date: August 18, 2005		Ciba Specialty Chemicals Holding Inc.

		(Registrant)


	By:	/s/ Oliver Strub Oliver Strub Head Corporate Law

	By:	/s/ Max Dettwiler Max Dettwiler Head Taxes, Insurance & Corporate Law

2Table of Contents

EXHIBIT INDEX

Exhibit	~~Description~~	Description
3.1	English Translation of the Amended Articles of Association
99.1		Half Year Financial Statements 2005.
99.1	English Translation of Ernst & Young Ltd. Report of the Statutory Auditors
99.2	English Translation of the Swiss Exchange Notice
99.3	Swiss Commercial Register

3Table of Contents

~~SIGNATURES~~CIBA SPECIALTY CHEMICALS HOLDING INC.

~~Pursuant~~On toAugust 18, ~~the~~2005, ~~requirements~~Ciba ofSpecialty ~~the~~Chemicals ~~Securities~~Holdings ~~Exchange~~Inc., ~~Act~~Basel, ofa ~~1934,~~stock corporation (the “Company”), ~~registrant~~issued ~~has~~its Half Year Results 2005. A ~~duly~~copy ~~caused~~of ~~this~~the ~~report~~Half toYear be2005 ~~signed~~Financial onStatements ~~its~~is ~~behalf~~attached byhereto ~~the~~as ~~undersigned,~~Exhibits ~~thereunto~~99.1 and ~~duly~~incorporated ~~authorized~~by reference herein.

Ciba Specialty Chemicals Holding Inc.

(Registrant)

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

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