The purpose of this research is to examine knowledge-sharing in organizations from a number of aspects, including innovation culture, roles, structure, and teamwork and leadership creativity. A survey was conducted of 100 Greek firms and we interviewed top and bottom management using a questionnaire which comprised twenty-eight questions divided into five categories. Most organizations appeared to have a knowledge system but its existence does not guarantee its use. This can be largely attributed to the fact that knowledge-sharing initiatives are preoccupied with technology infrastructure as the basic knowledge-sharing enabler. Most of them fail to focus on the individuals who engage in knowledge-sharing. It was found that resistance by management and employees was a critically important factor influencing the success or otherwise of organizational knowledge efforts. Knowledge-sharing is difficult to accomplish in such circumstances According to our cluster analysis, two types of firms are identified: those which have benefited from KM to invest in innovative strategies, and those which have not.