The Paper focusses upon strategies of adaptation to changing environments adopted by human service organizations. It analyses the influence of the task environment and of the organization's ideology upon the choice of strategies in general, and upon the issue of generalism versus specialism in particular, with respect to two particular human service organizations in Israel - Youth Aliyah and Community Service Organizations. The principal conclusion reached is that specialism is more suitable than generalism for attaining a fit between the organization and its task environment under conditions of rapidly changing,fine-grained environments.