In recent years, there has been a rapid growth of interest in Sweden in vertically integrated classes in compulsory schools, especially at junior high school and intermediate grade levels. This development is supported in various ways by the curriculum, partly because it puts more emphasis than previous curricula on the occurrence of teaching situations involving children at different ages. In addition, the time schedules contained in the curriculum and its syllabi for various teaching subjects now refer to levels of schooling instead of particular grades. This report presents discussions on: (1) why so many teachers prefer classes including children from several grades; (2) what educational benefits teachers anticipate; (3) the limitations involved in vertical integration; (4) what different working procedures are involved in these classes; and (5) how childrens' cognitive and social development will be affected. (JD)