Approximately 318 half-hour episodes (plus 7 feature films).
The production code order differs slightly from the airing order. Most notably, the series finale, Ben 10 vs. The Negative 10 , was a two-part special that wrapped up the original run, but the canon "true" ending is often considered the TV movie Secret of the Omnitrix , which reveals the origin of the Omnitrix. ben 10 list of episodes
These four series follow Ben Tennyson as he ages from 10 to 16, using various versions of the Omnitrix to defend Earth. (Original) 2005–2008 Approximately 318 half-hour episodes (plus 7 feature films)