The aim of this study was to investigate the relationship between crying of an infant and inflicted head injury by shaking and/or impact. During the period between January 1, 1997 and December 31, 2003, 26 cases of shaken baby syndrome (SBS) were identified in Estonia. The incidence of SBS was 28.7 per 100,000 children under 1 year of age during the whole study period. In this group there were four children from twin pairs: two twin boys and a girl from a twin pair and a boy from another twin pair. This represents 15.4% of the 26 cases. Twins in Estonia represent 2.12% of infant births. The mean age on admission was 3.9 months. According to outpatient records almost all parents (88.5%) in the study group (23/26) had contacted their family physicians and other specialists because of excessive crying or irritability of the baby prior to the admission to the hospital with SBS or death. We found that the time curve of crying was similar to the curve of highest incidence of cases of SBS except the crying curve began earlier. CONCLUSION. Our data confirm that the families with twins are at additional risk for SBS and parent's complaints of excessive crying of their infants should be taken as signal that parents need to be carefully counselled.