In this study activities related to biotechnology and genetic engineering were prepared and their effectiveness on students' achievement, attitudes towards biotechnology, and self-evaluations were investigated. The activities were implemented in 10th grade biology course. The study utilized mixed method, with qualitative and quantitative data collection tools. Two biology classes of the same teachers' in Ankara were chosen by convenient sampling technique. One experimental group and one control group is formed with random assignment. The quantitative data about students' achievement, attitudes towards biotechnology and self-evaluation were collected before and after the activities using pre-tests and post-tests. Then semi-structured surveys were conducted with experimental group students. Results show that the activities on biotechnology have no positive impact on the students' achievement. Also, students' self-evaluations indicate that they felt better in the activities, the abstract concepts were more concrete for them and it contributed to their learning by helping them to make investigations through inquiry. Based on the qualitative data, students stated that they liked the activities and they had fun. The study suggests integration of such activities to the teaching learning environment for supporting interest in biotechnology and genetic concepts.