Problem statement: Socio-cultural constructivism; stressing the social context, culture and collaborative side of learning, is another kind of constructivism. The social constructivist approach has positive effects on learners. It can be said that in improving problem solving and met cognitive awareness skills, which are amongst basic skills every individual should possess today. The purpose of this study is to investigate whether there is a significant difference in the learners' problem solving skills and met cognitive levels when the authentic task-based social constructivist approach is used in an experimental group and a traditional approach is used in a control group. Approach: In the research, semi-experimental design with pretest-posttest control groups has been used. The experimental group was applied, based on the constructivist approach, the authentic taskbased collaborative learning process more efficient. On the other hand, the control group was put in learning environments based on the meaningful learning approach. In the research, 89 teacher candidates were included in the experimental group and 48 teacher candidates were included in the control group. The "Problem Solving Scale", developed by Heppner and Peterson and adapted was used for acquiring the data about problem solving skills. "Metacognitive awareness scale", developed was used for acquiring the data about metacognitive levels. Results: At the end of the research, it was observed that the difference in the experimental group teacher candidates' problem solving skills and metacognitive levels was higher than the control group and statistically significant. Conclusion: According to this finding, it is appropriate to say that the task-based social constructivist approach has positive effects on teacher c candidates' problem solving skills and metacognitive levels.Key words: Meta Cognitive Awareness Scale (MAS), social constructivism, problem solving, metacognitive awareness, teacher trainingINTRODUCTIONSocio-cultural constructivism; stressing the social context, culture and collaborative side of learning, is another kind of constructivism (O'Donnell and King, 1999; McMahon, 1997; Sivan, 1986; Terwel, 1999). Recently, a lot of pedagogues have been regarding the social constructivist approach as a basis to design more effective learning environments (Woo and Reeves, 2007).Social constructivists often make use of Vygotsky's ideas to explain teach (Palmer, 2005). Vygotsky mostly focused on the effects of social interaction, language and culture on the learning process (Fosnot, 2005; Jonassen et al., 1995; Vrasidas, 2000; Woo and Reeves, 2007). According to Vygotsky (1978), the source of metacognitive processes is related to the culture. To him, a child's learning potential develops only if s/he is with the "other knowledgeable individuals". When we are with others, we can succeed much more than when we are alone. Achievements of human beings are substantially resulted from this kind of "cooperative" act (Liang and Gabel, 2005). In social constructivist educational theory, classroom is a learned society. According to social constructivists, learning occurs by means of peer interaction (collaboration), student ownership of the curriculum and educational experiences that are authentic to the students (Azzarito and Ennis, 2003).As mentioned above, one of the important notions of social constructivist approach is the authentic tasks (Brown et al., 1989; Woo and Reeves, 2007; Jaworski, 1994). According to this approach, meaningful learning occurs when there are real-world-related authentic tasks and by means of interaction and collaboration between experts and peers. Authentic tasks are described as "Anything students are expected to do, beyond getting input through reading or listening, in order to learn, practice, apply, evaluate, or in any other way respond to curricular content" (Brophy and Alleman, 1991). With these tasks, learners learn to solve the problems that are similar to real world problems (Steffe and Nesher, 1996; Glatthorn, 1994; Murphy, 1997). …