The background of this research is that there are still errors in the practice of making milk kefir in the biotechnology practice guide. Therefore, it is necessary to develop a free inquiry-based kefir worksheet that can be used by prospective teacher students in biotechnology courses. The method used is the research and development method which consists of define, design, and develop stages. Data collection techniques using the method of observation and questionnaires. The subjects of this study were the sixth semester biology education students. The results showed the validity of the questionnaire items had a score of 0.65 with the category of "high" validity. The feasibility test results obtained a value of 88.68% with the category "feasible". Readability test has a value of 87.65 with the category "very high". The average student performance score of 94% with the category of "very good", and the value of the use of worksheet scored 92.56%.