This study aimed to compare computer supported and concrete material assisted instructions in terms of effectiveness and classroom management. It was conducted with action research model and with 16 sixth grade pupils in a primary school in Trabzon in the 2008-2009 educational year. The data was based on the results of pre and post tests conducted with students, researcher observations and unstructured interviews. Two homogenous groups were formed according to the pretest; one to be concrete material (CM) group and the other one to be computer supported material (CSM) group. Afterward, answers to 11 questions, which were prepared to comply with the concerned learning gain were sought in both groups. Finally, the pre achievement test was re-applied. The results showed that CSM group students were more successful than CM group, classroom management was easier in CSM group and both of the groups enjoyed the applications. (C) 2010 Elsevier Ltd. All rights reserved.