Teachers' rooms are important parts of educational environments, as the quality of the physical-spatial and psychosocial conditions may affect the personal and occupational developments of teachers as well as the education processes. In Study 1 (n = 245), a Teachers' Rooms-Environmental Assessment Scale (TREAS) measure of the current conditions of teachers' rooms and the determination of the teachers' opinions on such conditions was developed and the initial validity evidence is presented. In Study 2 (n = 443) a confirmatory factor analyses showed support for the scale's two-factor approach. The scale factor conclusions were that the first factor should be labelled "communication"; the second factor labelled 'physical environment' as sub-scales. The internal consistency reliability was 0.95. The corrected item-total correlations ranged from 0.49 to 0.81. All studies of the analysis indicated that TREAS was a valid and reliable measurement for the teacher sample.