Learning chemistry should be able to provide opportunities for students to be creative in understanding the things they had been learned in the classroom. One of the efforts made for improving the quality of learning chemistry is implementing the problem-based learning model assisted with student worksheet. This research addressed to know the effectiveness of the student worksheet within problem-based learning model towards student's creative thinking skills. This research was kind of Research and Development (R&D) which implemented 4-D model that developed by Thiangarajan, Semmel, and Semmel which includes the defining, designing, and developing stage. The research instrument used a validated two-tier multiple choice questions. The enhancement of student's creativity was determined based on the results of the N-Gain analysis and the creative thinking skills assessment criteria. The result of the study showed that there was an enhancement towards student's creativity. It indicates that learning process conducted by problem-based learning model assisted with student worksheet was effectively used to improve student's creative thinking skills in learning chemistry.