The purpose of this study was to investigate the altruistic behavior which occurred in daily situations of a classroom. Thirty-six fifth grade elementary school children were observed for about 2400 minutes. Four measures of altruistic behavior were used:(a) behavioral mesure of altruistic behavior (observational data derived from natural observation in the classroom);(b) teacher rating;(c) self rating; and (d) peer nomination. The results were as follows:(1) Altruistic behaviors related teacher ratings and peer nominations.(2) Sex differences were observed. Girls displayed more altruistic behavior than boys. It was suggested that observational method of altruistic behavior was considerably effective. Methodological issues were discussed.