The 2004 Portland Grand Prix was the fifth race for the 2004 American Le Mans Series season held at Portland International Raceway. It took place on July 25, 2004.

Class winners in bold. Cars failing to complete 70% of winner's distance marked as Not Classified (NC).

Pos	Class	No	Team	Drivers	Chassis	Tyre	Laps
					Engine
1	LMP1	38	ADT Champion Racing	Marco Werner JJ Lehto	Audi R8	M	141
					Audi 3.6L Turbo V8
2	LMP1	16	Dyson Racing	Butch Leitzinger James Weaver	MG-Lola EX257	G	141
					MG (AER) XP20 2.0L Turbo I4
3	GTS	3	Corvette Racing	Ron Fellows Johnny O'Connell	Chevrolet Corvette C5-R	M	135
					Chevrolet 7.0L V8
4	GTS	4	Corvette Racing	Oliver Gavin Olivier Beretta	Chevrolet Corvette C5-R	M	133
					Chevrolet 7.0L V8
5	LMP2	30	Intersport Racing	Jon Field Clint Field Robin Liddell	Lola B2K/40	P	129
					Judd KV675 3.4L V8
6	LMP1	20	Dyson Racing	Chris Dyson Andy Wallace	MG-Lola EX257	G	129
					MG (AER) XP20 2.0L Turbo I4
7	GT	24	Alex Job Racing	Marc Lieb Romain Dumas	Porsche 911 GT3-RSR	M	128
					Porsche 3.6L Flat-6
8	GT	45	Flying Lizard Motorsports	Johannes van Overbeek Darren Law	Porsche 911 GT3-RSR	M	128
					Porsche 3.6L Flat-6
9	GT	31	White Lightning Racing	David Murry Craig Stanton	Porsche 911 GT3-RSR	M	127
					Porsche 3.6L Flat-6
10	GT	23	Alex Job Racing	Jörg Bergmeister Timo Bernhard	Porsche 911 GT3-RSR	M	127
					Porsche 3.6L Flat-6
11	GT	66	New Century - The Racer's Group	Patrick Long Cort Wagner	Porsche 911 GT3-RSR	M	127
					Porsche 3.6L Flat-6
12	GT	44	Flying Lizard Motorsports	Seth Neiman Lonnie Pechnik	Porsche 911 GT3-RSR	M	124
					Porsche 3.6L Flat-6
13	GT	79	J-3 Racing	Justin Jackson Tim Sugden	Porsche 911 GT3-RSR	M	124
					Porsche 3.6L Flat-6
14	GT	60	P.K. Sport	Peter Boss Hugh Plumb	Porsche 911 GT3-RS	P	123
					Porsche 3.6L Flat-6
15	GT	67	New Century - The Racer's Group	Jim Matthews Pierre Ehret	Porsche 911 GT3-RSR	M	119
					Porsche 3.6L Flat-6
16	GTS	63	ACEMCO Motorsports	Terry Borcheller Johnny Mowlem	Saleen S7-R	P	113
					Ford 7.0L V8
17	LMP2	10	Miracle Motorsports	Ian James James Gue John Macaluso	Lola B2K/40	Y	112
					Nissan (AER) 3.0L V6
18 DNF	GTS	6	Krohn-Barbour Racing	Tracy Krohn Niclas Jönsson	Lamborghini Murcielago R-GT	P	103
					Lamborghini 6.0L V12
19 DNF	GTS	5	Krohn-Barbour Racing	Peter Kox David Brabham	Lamborghini Murcielago R-GT	P	91
					Lamborghini 6.0L V12
20 DNF	GT	43	BAM!	Leo Hindery Marc Lieb	Porsche 911 GT3-RSR	M	83
					Porsche 3.6L Flat-6
21 DNF	LMP2	56	Team Bucknum Racing	Jeff Bucknum Bryan Willman	Pilbeam MP91	D	56
					Nissan (AER) 3.0L V6
22 DNF	GT	35	Risi Competizione	Anthony Lazzaro Ralf Kelleners	Ferrari 360 Modena GTC	P	36
					Ferrari 3.6L V8
23 DNF	GT	50	Panoz Motor Sports	Gunnar Jeannette Kelly Collins	Panoz Esperante GT-LM	P	27
					Ford (Elan) 5.0L V8

• Pole Position - #20 Dyson Racing - 1:04.750
• Fastest Lap - #38 ADT Champion Racing - 1:05.129
• Distance - 274.104 miles (441.128 km)
• Average Speed - 99.082 mph (159.457 km/h)

• "Official Results" (PDF). Archived from the original (PDF) on 2007-09-29. Retrieved 2006-11-17. (31.0 KiB)