The dynamics of the processes taking place in an environment, which is rendered in the altered perception of the character of this environment, induces a need to find answers to the following questions: (1) How do managers perceive an environment in the dimensions of stability/ changeability and friendliness/unfriendliness? (2) Is there a correlation between the stability/changeability and friendliness/unfriendliness of an environment, i.e. if an environment is more stable, is it perceived as more friendly, and if an environment is more changeable is it perceived as unfriendly? (3) Does environmental stability/changeability as well as friendliness/unfriendliness exert any influence on organizational effectiveness? In an attempt to answer the above quoted questions, the article’s objective has been defined as a discussion on the interdependencies perceived by managers between an environment’s dimensions of stability/changeability and friendliness/unfriendliness (analysed in terms of institutional categories) and the organizational effectiveness of Polish enterprises. The managers evaluated the legal environment as the least stable. In their opinion, that milieu was also more intimidating than friendly. Concurrently, a technological environment was perceived by the respondents as the most stable and favourable. The results of the effected research allow forming a conclusion concerning the existing correlation between the friendliness and stability of particular categories of an environment, at the same time pointing out to the occurrence of correlations between stability/changeability and friendliness/ unfriendliness of some categories of an environment and the organizational effectiveness of the examined enterprises.