Being convinced that the research on workers' behaviors is a part of management in organizational settings, in order to make organizations work more effectively, the authoress referred the organizational behavior to the achievements of positive psychology as to the attempt to focus on building positive qualities and traits within individuals or organizations. Positive psychology has introduced the paradigm of the reflection on human, different than already known, which has recommended to abandon the research into the imperfection of human existence, suggesting the concentration on the individual's strong points in exchange for it. The possession of such points is nowadays considered to be the only way for the individual to achieve their successes, because it is aimed at making the most of the individual's potential and therefore accomplishing the best results in their cases. The reason is that the new manner of the interpretation of behaviors is based on the assumption that it is easier to achieve success by developing one's own advantages than by diminishing one's weaknesses. Aiming at the genuine treatment of workers as the most valuable resource in an organization requires employers to use the achievements of positive psychology. By dint of such attitude it is possible to strengthen advantages of every company, within soft competencies of both the superiors and the subordinates. Optimism belongs to these advantages doubtless, so this study focuses on the state of optimism. The principal aim of the research is the assessment of the influence of workers' optimism on organizational performance and positive climate of organization. The research was conducted in 2005,120 small and medium enterprises, with selection of subordinates and superiors, were chosen from the area of the North-East Poland. One of the most relevant conclusions is the assertion that it is possible to transmit optimism as well as statement that optimism infects people by dint of such mechanisms as: involved participation in a group, identification, imitation, the tasks which increase prestige, suggestion, similarity and normative pattern and behavioral pattern.