ONE STUDY EXAMINED PHYSICAL VIOLENCE BETWEEN 88 PAIRS OF SIBLINGS WHILE THE OTHER INVOLVED RECOLLECTIONS FROM A RANDOM SAMPLE OF COLLEGE STUDENTS. THE COLLEGE STUDY FOUND 62 PERCENT HAD USED PHYSICAL FORCE ON A BROTHER OR SISTER DURING THE PAST YEAR. THE SIBLING STUDY FOUND VIOLENCE INCREASED FROM 63 PERCENT IN FAMILIES IN WHICH CHILDREN WERE ALL OVER AGE 14 TO 70 PERCENT IN FAMILIES WITH ALL CHILDREN UNDER AGE 8. OF THESE 0.3 PERCENT USED A KNIFE OR GUN ON A SIBLING. WHILE THIS MAY NOT SEEM HIGH, THERE WERE AN ESTIMATED 138,000 CHILDREN IN THE UNITED STATES WHO HAD ACTUALLY USED A GUN OR KNIFE ON A SIBLING DURING THE SURVEY YEAR (1977). THE 14 PERCENT WHO BEAT UP A SIBLING IS CONSISTENT WITH WESTON'S 1968 REPORT THAT 14 PERCENT OF BATTERED CHILDREN EXAMINED HAD RECEIVED THE BATTERING FROM A SIBLING. WHILE NATIONAL STATISTICS FOR SIBLING HOMICIDES ARE NOT AVAILABLE, OVER 3 PERCENT OF PHILADELPHIA HOMICIDES BETWEEN 1948 AND 1952 WERE COMMITTED BY SIBLINGS. SIBLING VIOLENCE IS LINKED TO SPOUSE ABUSE AND CHILD ABUSE. IT IS SUGGESTED THAT THE CHILD WHO IS ALLOWED TO USE VIOLENCE IN THE HOME IS LIKELY TO GROW INTO AN ADULT WHO USES VIOLENCE TO SOLVE DOMESTIC DISPUTES. STATISTICS FOR WIFE ABUSE, HUSBAND ABUSE, AND CHILD ABUSE ARE BRIEFLY REVIEWED. IT IS POINTED OUT THAT DOMESTIC VIOLENCE IS A MAJOR SOCIAL PROBLEM. PARENTS ARE URGED NOT TO CONSIDER SIBLING VIOLENCE 'NORMAL' AND TO ATTEMPT TO BREAK THE CHAIN WHICH LEADS TO ESCALATED USE OF PHYSICAL FORCE. REFERENCES ARE APPENDED. (GLR)