The 2005 Portland Grand Prix was the sixth race for the 2005 American Le Mans Series season held at Portland International Raceway. It took place on July 30, 2005.

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	2	ADT Champion Racing	Frank Biela Emanuele Pirro	Audi R8	M	137
					Audi 3.6L Turbo V8
2	LMP1	20	Dyson Racing	Chris Dyson Andy Wallace	MG-Lola EX257	M	137
					MG (AER) XP20 2.0L Turbo I4
3	LMP1	16	Dyson Racing	Butch Leitzinger James Weaver	MG-Lola EX257	M	136
					MG (AER) XP20 2.0L Turbo I4
4	LMP2	37	Intersport Racing	Clint Field Gregor Fisken	Lola B05/40	G	132
					AER P07 2.0L Turbo I4
5	GT1	4	Corvette Racing	Oliver Gavin Olivier Beretta	Chevrolet Corvette C6.R	M	131
					Chevrolet 7.0L V8
6	GT1	3	Corvette Racing	Ron Fellows Johnny O'Connell	Chevrolet Corvette C6.R	M	131
					Chevrolet 7.0L V8
7	LMP1	12	Autocon Motorsports	Bryan Willman Michael Lewis	Riley & Scott Mk III C	D	130
					Elan 6L8 6.0L V8
8	GT1	5	Pacific Coast Motorsports	Alex Figge Ryan Dalziel	Chevrolet Corvette C5-R	Y	130
					Chevrolet 7.0L V8
9	GT1	35	Maserati Corse Risi Competizione	Fabrizio de Simone Mika Salo	Maserati MC12	P	129
					Maserati 6.0L V12
10	GT2	23	Alex Job Racing	Timo Bernhard Romain Dumas	Porsche 911 GT3-RSR	M	125
					Porsche 3.6L Flat-6
11	GT2	43	BAM!	Martin Jensen Wolf Henzler	Porsche 911 GT3-RSR	Y	124
					Porsche 3.6L Flat-6
12	GT2	45	Flying Lizard Motorsports	Johannes van Overbeek Jon Fogarty	Porsche 911 GT3-RSR	M	124
					Porsche 3.6L Flat-6
13	GT1	71	Carsport America	Michele Rugolo Tom Weickardt	Dodge Viper GTS-R	P	123
					Dodge 8.0L V10
14	GT2	50	Panoz Motor Sports	Bryan Sellers Robin Liddell	Panoz Esperante GT-LM	P	123
					Ford (Elan) 5.0L V8
15	GT2	51	Panoz Motor Sports	Marino Franchitti Christophe Tinseau	Panoz Esperante GT-LM	P	122
					Ford (Elan) 5.0L V8
16	GT2	79	J3 Racing	Justin Jackson Michael Galati	Porsche 911 GT3-RSR	P	120
					Porsche 3.6L Flat-6
17	GT2	44	Flying Lizard Motorsports	Lonnie Pechnik Seth Neiman	Porsche 911 GT3-RSR	M	120
					Porsche 3.6L Flat-6
18	LMP2	8	B-K Motorsport	Guy Cosmo Jamie Bach	Courage C65	G	117
					Mazda R20B 2.0L 3-Rotor
19	GT2	31	Petersen Motorsports White Lightning Racing	Patrick Long Jörg Bergmeister	Porsche 911 GT3-RSR	M	113
					Porsche 3.6L Flat-6
20 DNF	GT2	24	Alex Job Racing	Ian Baas Darren Law	Porsche 911 GT3-RSR	M	95
					Porsche 3.6L Flat-6
21 DNF	LMP2	10	Miracle Motorsports	Jeff Bucknum Chris McMurry	Courage C65	K	86
					AER P07 2.0L Turbo I4
22 DNF	GT1	63	ACEMCO Motorsports	Terry Borcheller Johnny Mowlem	Saleen S7-R	M	48
					Ford 7.0L V8
23 DNF	LMP1	1	ADT Champion Racing	Marco Werner JJ Lehto	Audi R8	M	48
					Audi 3.6L Turbo V8

• Pole Position - #20 Dyson Racing - 1:02.712
• Fastest Lap - #20 Dyson Racing - 1:04.271
• Distance - 269.068 miles (433.023 km)
• Average Speed - 97.78 mph (157.36 km/h)

• "Official Results" (PDF). Archived from the original (PDF) on 2006-11-10. Retrieved 2006-11-04. (51.2 KiB)