The purpose of the study is to investigate how pre-service teachers adopt YouTube technology into their microteaching as part of their assignments. The participants were twelve Taiwanese pre-service teachers in a Teaching English to Speakers of Other Languages graduate program. They enrolled in a Second Language Writing course and worked in groups to develop and upload microteaching videos on YouTube. In addition, the pre-service teachers had to recruit students to learn from their YouTube lessons in order to make observations on their learning. The results were fourfold: (1) the pre-service teachers employed a variety of styles and approaches in their YouTube lessons; (2) the pre-service teachers held mildly positive attitudes toward the YouTube microteaching project and revealed their gains in the perceptual shift about teaching, connecting theory and practice, and gaining hands-on experience in computer-assisted language learning; (3) the pre-service teachers encountered varying degrees of technical difficulty in producing the YouTube microteaching videos; and (4) a number of factors affecting the delivery and quality of the microteaching lessons were found (e.g. sources of anxiety, shifts in motivation, a strong focus on visuals and personal appearance, lack of student feedback and interaction).