Exhibit 99.1

                AMIS Holdings, Inc. Executive Adopts 10b5-1 Plan

    POCATELLO, Idaho--(BUSINESS WIRE)--Sept. 17, 2004--AMIS Holdings,
Inc. ("AMIS" or "Company") (Nasdaq:AMIS), parent company of AMI
Semiconductor, a leader in the design and manufacture of integrated
mixed-signal solutions, today announced that Charlie Lesko, senior
vice president of sales and strategic marketing, has adopted a
pre-arranged stock trading plan in accordance with Rule 10b5-1 of the
Securities and Exchange Act of 1934, as amended. The plan allows for
the sale of 25,000 shares of AMIS common stock.
    Lesko adopted the plan in order to diversify his assets for
personal financial purposes. In accordance with the trading plan, the
shares will be sold in November 2004 and will be under the direction
of Merrill Lynch, Pierce, Fenner & Smith, Inc. The shares to be sold
under the plan represent 13 percent of the total shares held by and
the unexercised options awarded to Lesko since the beginning of his
employment with the Company.
    SEC Rule 10b5-1 allows corporate executives to establish
pre-arranged plans to sell a specified number of shares of company
stock in accordance with a plan schedule. These plans permit
executives to change their investment portfolio gradually. This
minimizes the market effects of stock sales by spreading sales out
over a more extended period of time rather than carrying out sales
during limited trading windows following quarterly earnings
announcements. It also avoids concerns about initiating stock
transactions while the executive may be aware of material nonpublic
information. Once a plan is established, the executive does not retain
or exercise any discretion over sales of stock under the plan and the
pre-planned trades can be executed at later dates as set forth in the
plan, without regard to any subsequent material non-public information
that the executive might receive.

    About AMI Semiconductor

    AMI Semiconductor (AMIS) is a leader in the design and manufacture
of silicon solutions for the real world. As a widely recognized
innovator in state-of-the-art integrated mixed-signal products,
mixed-signal foundry services and structured digital products, AMIS is
committed to providing customers with the optimal value, quickest
time-to-market semiconductor solutions. Offering unparalleled
manufacturing flexibility and dedication to customer service, AMI
Semiconductor operates globally with headquarters in Pocatello, Idaho,
European corporate offices in Oudenaarde, Belgium, and a network of
sales and design centers located in the key markets of the United
States, Europe and the Asia Pacific region.


    CONTACT: AMI Semiconductor, Pocatello
             Investor Relations:
             Jimmie Hutchens, 208-234-6732
             jimmie_hutchens@amis.com
             or
             Media Relations:
             Tamera Drake, 208-234-6890
             tamera_drake@amis.com