Verbalizations of six undergraduate students that collaboratively solved an ill-structured problem were described. It was assumed that verbalizations provided information about metacognitive regulation and problem solving. The verbalizations were categorized into levels to identify verbal expressions that demonstrate both metacognitive regulation and ill-structured problem solving processes. State space grids were used to represent and interpret verbalization levels and illstructured problem solving processes. Results showed predominance of unregulated verbalizations, absence of utterances related to justification generation and superficial monitoring and evaluation. The evidence supports the idea that peer interaction itself does not improve problem solving. The results invite to design problem-solving situations that effectively promote metacognitive regulation.