This research aims to compare three kinds of knowledge of cognition underlying the reflective aspects of metacognition. The three kinds of cognition considered in this research are declarative knowledge, procedural knowledge and conditional knowledge. This exploratory research survey involved 122 pre-service biology teachers during their third semester of training. The instrument used to gather data was the Metacognitive Awareness Inventory (MAI) of Schraw and Denisson (1994), modified by use of a Likert scale. The data gathered were analyzed using one-way analysis of variance (ANOVA) followed by a least significant difference (LSD) test. The results of this research show that the kind of knowledge of cognition of preservice biology teachers which was most highly developed in the research sample was conditional knowledge, followed by procedural knowledge and declarative knowledge, between which there was no significant difference. This high level of conditional knowledge as compared with the other two knowledge types could result from this type of knowledge being stimulated to a greater extent than the other two types. Based on the results of this research, it is recommended that, in order to stimulate knowledge of cognition, especially conditional knowledge, lecturers in biology education should provide challenging learning environments containing clear problems and tasks, and simultaneously implement a reward system for students.