From The TV IV

'Season One or Invader Zim premiered on March 30, 2001.

[edit] Episodes

#	#	Title	Airdate
0	0	Pilot	unaired
1	1	The Nightmare Begins	March 30, 2001
2	2	Bestest Friend / Dark Harvest	April 13, 2001 / April 20, 2001
3	3	Parent Teacher Night / Walk of Doom	April 6, 2001
4	4	Germs / Nanozim	April 20, 2001 / April 13, 2001
5	5	Attack of the Saucer Morons / The Wettening	April 27, 2001
6	6	Career Day / Battle-Dib	May 4, 2001
7	7	Planet Jackers / Bad, Bad Rubber Piggy	August 31, 2001 / August 24, 2001
8	8	Rise of the Zitboy / Invasion of the Idiot Dog Brain	August 31, 2001 / August 24, 2001
9	9	A Room with a Moose / Hamstergeddon	August 17, 2001
10	10	Plague of Babies / Bloaty's Pizza Hog	September 7, 2001
11	11	Door to Door / FBI Warning of Doom	March 29, 2002
12	12	Bolognius Maximus / Game Slave 2	September 21, 2001
13	13	Battle of the Planets	April 5, 2002
14	14	Mysterious Mysteries / Abducted	March 22, 2002 / April 12, 2002
15	15	Hobo 13 / Future Dib	July 12, 2002 / March 22, 2002
16	16	Halloween Spectacular of Spooky Doom	October 26, 2001
17	17	The Sad, Sad Tale of Chickenfoot / Gir Goes Crazy and Stuff	April 12, 2002 / May 24, 2002
18	18	Walk for Your Lives / Lice	September 28, 2002 / April 26, 2002
19	19	Dib's Wonderful Life of Doom / Megadoomer	May 24, 2002 / April 26, 2002
20	20	Tak: The Hideous New Girl	May 10, 2002

Note: Episodes are listed in production order.