Exhibit 99.1
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ASML Announces TWINSCAN XT:1400 for Dry or Wet Lithography

VELDHOVEN, the Netherlands - April 20, 2004 - ASML Holding NV (ASML) today
introduced the newest member of its TWINSCAN(TM) platform, the TWINSCAN XT:1400.
The system is a 0.93 NA, 193 nm scanner that images at the 65 nm node in volume
production environments. The XT:1400 can also be used for pre-production testing
and development at the 45 nm node. The first shipments are slated for December
2004.

The XT:1400 has a unique architecture found only in ASML systems. The design
provides customers with the option of transitioning the system from "dry" to
immersion lithography on the fab or factory floor through an `immersion
conversion' kit available in Q4 2005. The XT:1400 gives customers the
flexibility to include immersion into their technology roadmaps while protecting
their investments in dry 193 nm technology.

"ASML innovations focus on evolving customer needs. The XT:1400 is packed with
choices. Customers can either volume-produce chips at the 65 nm node or develop
their processes for chip manufacturing at the 45 nm node," said Martin van den
Brink, executive vice president, marketing and technology, ASML.

"The strategy behind our high NA, immersion-prepared system means chipmakers
move towards new technologies at their own pace and with minimum investment.
This significantly lowers the risk traditionally associated with wavelength
reductions. The XT:1400 constitutes ASML's third generation of immersion tools
- the 1150i was our prototype and the XT:1250i was our pre-production tool, both
were announced last year," van den Brink concluded.

The immersion conversion kit for the XT:1400 is comprised of three main
components - a lens suitable for immersion use, immersion-compatible wafer
stages and immersion infrastructure. Conversion from a dry to a wet platform can
be achieved in a matter of weeks and will increase the process latitude of the
system.

The XT:1400 comes equipped with Ultra-k1(TM), ASML's hardware and software
portfolio of imaging enhancement technologies that allows the shrinking of
circuit features, ensures high die yields and maximizes bottom-line return.

About ASML

ASML is the world's leading provider of lithography systems for the
semiconductor industry, manufacturing complex machines that are critical to the
production of integrated circuits or chips. Headquartered in Veldhoven, the
Netherlands, ASML is traded on Euronext Amsterdam and NASDAQ under the symbol
ASML.

ASML
Tom McGuire
Vice President Communications
corpcom@asml.com
tel: +31.40.268.5758
fax: +31.40.268.3655

ASML
Elizabeth Kitchener
Director Corporate Communications
corpcom@asml.com
tel: +1.203.761.6300
fax: +1.203.761.4207

ASML
Craig DeYoung
Vice President Investor Relations
craig.deyoung@asml.com
tel: +1.480.383.4005
fax: +1.480.383.3976

ASML
Franki D'Hoore
Director European Investor Relations & EU Affairs
franki.dhoore@asml.com
tel: +31.40.268.6494
fax: +31.40.268.3655