Objective: This study was conducted to investigate the effects of small-group arithmetic word problem activities with concrete materials on 5 year old children’s mathematical ability and attitude. Methods: A total of 34 five-year-old children (controlgroup 16 children, experimental group18 children) attending two kindergartens in P city participated in this study. Fifteen small-group arithmetic word problem activities with concrete materials were conductedin the classroom of the experimental group twice a week for eight weeks. Before and after the activities, all the participants individually took a basic arithmetic test, mathematical word problem solving test, and mathematical attitudes test. Results: First, we observed thatthe children in the experimental group achieved significantly higher scores on the mathematical ability tests, including the basic arithmetic test and mathematical word problems solving testwhencomparedtothe children in the control group. Second, we also found that children in the experimental group showed higher improvement in the mathematical attitudes test than their counterparts. Conclusion/Implications: The resultsof this study suggest that small-group arithmetic word problem activities with concrete materials are effective in improving children’s mathematical ability and attitudes.