One of the most difficult problems to overcome during children growth is temper tantrums. Temper tantrums is a children behavior that need to be resolved for better development of children as an individual. Cooperative play is one of methods that can reduce tamper tantrum by improving cooperative and completing mission together. The purpose of this study was to determine the effect of cooperative play on temper tantrums reaction among preschool children at TK Dharma Wanita Arjasa. This study was quasi experiment with pretest-posttest control group design. Temper tantrums rating scale used as data collecting tool. Fifty children were pointed as the sample, which consisted 25 children for control group and 25 children as experimental group. The purposive sampling technique used as sampling technique. Cooperative play carried out regularly for ten sessions during two weeks. Mann Whitney U- Test used as statistical data analysis. The result of Mann Whitney U- Test showed that there was an effect of cooperative play on temper tantrums reaction among preschool children at TK Dharma Wanita Arjasa (p value=0.012). Cooperative play can decrease temper tantrums reaction among preschool children. Nurses should regularly giving information for parents about the importance of cooperative play for reducing temper tantrums reaction among preschool children.