Purpose: The purpose of this paper is to analyse how newcomers' perceptions of organisational culture can change over time. The study tries to address whether initial working experience changes newcomers' perceptions about the ideal organisational culture, and whether these perceptions converge with those of their supervisors. Design/Methodology/Approach: A longitudinal survey was carried out on a sample of undergraduate students to measure shifts in their perceptions of organisational culture over time. In order to interpret the results in terms of actual organisational culture, a survey was also conducted with the students' immediate supervisors. Findings: Applying a factor analytic procedure to the aggregate sample of study, the items of an existing scale were reduced to a six-dimensional structure. Based on the results of statistical analysis, the study revealed that initial working experience might affect students' perception of organisational culture and make these perceptions converge with those of their immediate managers. Specifically, the students' perceptions about the importance of stability and success orientation dimensions changed over time. By the end of the process, they found supportiveness and people orientation more important, similarly to their supervisors. Practical implications: This study reveals the critical role of supervisors in the transmission of organisational culture to newcomers. Additionally, it demonstrates the importance of work-based learning for acquiring work-related and technical beliefs, as well as obtaining initial ideas about the culture of a real organisation. Originality/Value: The study can specifically contribute to the growing literature on organisational culture by demonstrating the impact of initial working experience on newcomers' perceptions, and how they adopt the culture of their new organisations to become a part of this culture.