Lack of confidence towards science is a major factor in the avoidance of teaching science at elementary school. This paper reports the results of a survey that asked 28 pre-service elementary teachers what they believed contributed to their confidence towards science and the teaching of science during a second year science unit where an holistic teaching/learning approach was taken. The holistic nature of the unit was based on a model that considered six major factors to be important influences on the confidence of the pre-service teacher. Using median values, and ranking from the most to least important factor influencing their confidence, the pre-service teachers identified practicum, teacher educator, pedagogical content knowledge, learning environment, assessment and reflection. Factors within pedagogical content knowledge, ranked from most to least important, were science pedagogy, science activities, children's views of science, science content knowledge and investigating scientifically. The wide variability in responses highlighted that no single factor was perceived to be a major contributor to the pre-service teachers' confidence, but rather a balanced mix was necessary. Implications for pre-service elementary science education units are discussed.