Lately, much is said about the use of YouTube by children and the influ-ences that youtubers can have on their lives, but little is discussed about it academ-ically. This research aimed to investigate the content that children watch on YouTube, and to discuss how that material allows us to think about different child-hoods. Mixed methods were used, which consisted of two stages: a survey answered by 344 children and semi-structured collective and individual interviews with 30 children. The participants were 8 to 10 years old and belonged to different social classes in the city of Rio de Janeiro. The data were analyzed considering the varia-bles of gender and social group. Thematic analysis method was used to look at the interviews. The findings point to children s preference for funny videos, challenges and trolling videos - all with strong playful aspects. It appears that kids cultures are present in the content that children watch and in the uses that they make of YouTube. They watch videos for fun, share their preferences with their peers, and see youtubers as very different from them. Children build rich hypotheses about how the platform works, appropriating themselves in unique ways and showing a critical look at the content they watch. The importance of including children in con-versations about YouTube is emphasized, considering their appropriation of this space. Thus, one can think about media education and content production that take childhood(s) into account.