Taking coping research as the point of departure, a questionnaire on the strategies of anger regulation preferred by school-age-children (KÄRST) is presented. This self-report measure was tested with a sample of 141 youngsters of grade 3 to grade 6. Results suggest a factor solution which was stable over time and easy to interpret. Test-retest reliabilities of the four factors ranged between .68 and .78; Cronbach's α varied between .59 and .80. In light of the fact that children of this age are still developing their powers of self-observation and self-report, these results were considered satisfactory. Correlations with social desirability were generally low. In order to further test the validity of the self-reported strategies (KÄRST-Selbst), a parallel questionnaire was developed which asked the children's friends about the strategies the children preferred when they were angry at them (KÄRST-Fremd). The friend's report is limited to the observable strategies of anger regulation. Results indicate that children's self reports were supported by significant correlations with their friend's reports for four of the seven strategies at two points of measurement and for two further strategies at one point. Further analyses suggest that the choice of anger regulation strategies is specific to a particular friendship. Outsiders seem to be unable to assess correctly which strategies children prefer in a particular friendship, even when they also call themselves friends.