Season 0 of Sayonara Zetsubou Sensei premiered on January 1, 2008.

Season 1 of Sayonara Zetsubou Sensei premiered on July 7, 2007.

Itoshiki Nozomu is always in despair! Even simple things like paying for the toll on the subway can send him to a despair so deep only attempted suicide is the answer. How Strange is it then, that he should be the teacher of a High School Class filled with students with even more emotional problems than his. This great Comedy will leave you in anything but 'Despair' as you meet each of his students and watch their wacky adventures.

Season 2 of Sayonara Zetsubou Sensei premiered on January 5, 2008.

More crazy antics abound as Nozomu Itoshiki, a.k.a Zetsubou-sensei, who is the worlds most negative person, tries to teach class 2-F about how life is filled with despair and darkness. A harder task than it first may seem, with his students being far from ordinary themselves, including the likes of the most positive girl he has ever met, his very own stalker, a foreign exchange student with split personalities and a perfectionist acting class president, due to the fact the real class president can't be seen by anyone, among others.

Season 3 of Sayonara Zetsubou Sensei premiered on July 5, 2009.

Nozomu Itoshiki is still the bizarre teacher of the even stranger Class 2-F. He attempts to teach his students the negative aspects of the world and society, only to have each circumstance thrown at his face whenever he tries. With more students and friends than before, Zetsubo-sensei's life becomes harder and crazier than ever before.