This study was an attempt to find out the misconceptions of biology students at secondary level. It is a well known fact that students enter in science classroom with a lot of misconceptions, which are based on their beliefs and observations. The focus of this research study was to find out the misconceptions of students about selected concepts of biology e.g. classification of animals, photosynthesis and green house effect. The nature of the research study was exploratory and interviews were conducted to investigate the misconceptions. The 2 schools were purposely selected as a study site. The size of the sample of the study was 80 students (50% boys & 50% girls), who participated in the study voluntarily. A well established technique ‘Interview About Instances’ (IAI) was used to explore misconceptions of the students. To apply this interview technique instance cards (20 for each concept) were developed to present examples and non- examples of biology concepts in the form of diagrams, line diagrams and pictures. Non-formal, semi-structured interviews were conducted with each participant to explore the existing misconceptions of the students. Interviews were audio-taped with permission and later on transcribed. The codes were assigned to the responses on the basis of similarities and differences. The responses were combined to find out the underlying themes which combined into three categories. The inquiry sessions were planned. The participants were randomly divided into two equal groups’ i.e. Group A & Group B. Group B participated in inquiry sessions while group A was kept outside. Researcher facilitated the inquiry sessions, students planned activities to explore the concepts. Afterwards, the same instance cards were shown to both A & B groups. Interviews about instances were conducted, recorded, transcribed and coded. The responses of students were consolidated into themes which were combined into three categories. The frequencies and percentages of categories of responses in pre and post session interviews were calculated and compared. Moreover to establish the effectiveness of inquiry approach as a conceptual change instructional strategy the responses of Group A & B in post session were also compared. The improvement in scientific responses and correctness of misconceptions was observed in the responses of group B in post session interviews. It was concluded that students had misconceptions in basic biological concepts. The misconceptions found were large in number which can be addressed with appropriate conceptual change instructional strategy. It was also concluded that inquiry method is an effective strategy to replace the misconceptions with accurate conceptions. It was recommended that misconceptions of students should be explored and addressed appropriately prior to teaching.