Programs and educational practices that enable gifted students to conduct science activities and develop themselves in engineering fields are rapidly increasing in Malaysia. One of them is the science camp to improve STEM skills. This study investigates the effectiveness of science camp (Junior Science Camp) towards young children's understanding and knowledge about science. One hundred and three children aged four to six years old participated in the three-day camp. Mixed research model was used in this research. Data were collected by Junior Science Camp Scientist Test (JSCST) as pre and post-test, parent evaluation of the camp. Questions in the pre and post-test were on the content in the five camp modules: I am an engineer, I am a scientist, I am a chemist, I am a forensic scientist, and I am a natural scientist. Data from the open-ended question in the survey (parent evaluation) were used to triangulate the quantitative data from the pre and post-test. Findings showed that the camp was effective in enhancing the young children's (preschoolers') understanding about science and increasing their knowledge about science and STEM fields. Implications of this study are related to the design of future science camps and also the methodology and instruments of future research.