An interesting and little documented problem is the influence of a design methodology on the program architecture. In this case study, we compared two design methodologies and their impact on both development process and the resulting program architecture. The methodologies are object-based variants of refinement methodology and structured design, respectively. Both methodologies were applied to the same problem (a library system of less than 1000 lines of Ada code), and the results were compared. Substantial differences between the two resulting architectures are analysed and discussed.