No, the Buddha was not vegetarian. He was an alms-mendicant - this means he ate only what people gave him, and did not store food for another day.
''As recorded in the Pali scriptures, the Buddha did not prohibit consumption of meat, even by monks. In fact, he explicitly rejected a suggestion from Devadatta to do so. In modern Theravada societies, a bhikkhu who adheres to vegetarianism to impress others with his superior spirituality may be committing an infringement of the monastic rules.
On the other hand, the Buddha categorically prohibited consumption of the flesh of any animal that was "seen, heard or suspected" to have been killed specifically for the benefit of monks (Jivaka Sutta, Majjhima Nikaya 55). This rule technically applies only to monastics, but it can be used as a reasonable guide by devout lay people.''http://www.urbandharma.org/udharma3/vegi.html