Introduction: finding ways to teach clinical reasoning has been an primary concern of nursing educators for many years. Context: hypothesis generation is a critical milestone in clinical reasoning in nursing which students still struggle with at the end of their program. Aim: the study aimed at documenting nursing students’ capacity to formulate hypotheses during a vignette-based activity.Method: for this qualitative exploratory study, seventeen nursing students in the last semester of their program were recruited and divided in four groups. Each group participated once in the activity. The combined methods used for data collection were participative observation, videotaping of the activity, and a written questionnaire immediately after the activity. The clinical reasoning in nursing skills described by Fonteyn (1998) were used as the theoretical framework to analyze data. Results: results suggest that the vignette-based activity does stimulate students to formulate hypotheses. It also stimulates sharing and recollection of knowledge amongst students. Discussion: further research would be necessary to verify whether the activity could be used with students at the beginning of their nursing education. Conclusion: this type of activity could be useful in promoting the development of clinical reasoning as a complement to other educative activities used in nursing education programs.