The aim of this paper is to present the core specifications for designing methods of assessing young learners' proficiency in Greek. It is proposed that language proficiency is assessed on the basis of a rating scale provided by the Common European Framework of Reference for Languages (2001). This scale, designed primarily for adults, is adapted for young learners, and provides the point of departure for designing and developing three tests, one for every two grades of the six-grade primary school. In this paper, the main stages of test development and the test specifications with respect to features of tasks (such as instructions, text and task types etc.) are presented.