The number of cases of murder, manslaughter, and infanticide reported in this study were pieced together through an examination of five sources: Return of Outrages Reported to the Constabulary Office (1836-1922); Statistical Returns of the Dublin Metropolitan Police (1838-1918); Judicial Statistics, Ireland (1863-1919); Registrar General's Reports (1925-1946); and Annual Reports of An Garda Siochana (1947-2003). The analysis disaggregated infanticide from other homicides. The trend in homicide in Ireland (declining over a period of 100 years to reach an all-time low in the 1950s and then showing an upturn in the final decades of the 20th century) mirrors so closely the homicide pattern in other countries that it provides additional support for the theory outlined by Elias, namely, that the development of increased self-control and the monopolization of violence by the state, leads to fewer impulsive killings and the gradual pacification of interpersonal interactions. When infanticide is disaggregated from other killings, however, a different pattern emerges, in that the decline was not reversed as it was for other homicides. This paper argues that this was related to an increasing respect for infant life and a marked increase in celibacy after the Famine of 1845-50. Other killings remained at a relatively high and stable level for the latter half of the 19th century. This is attributed to the persistence of "recreational" violence (street brawling and faction fights). The decline in homicide in Ireland from the turn of the 20th century is related to emigration and the founding of an independent Irish state after 1922. 2 tables, 6 figures, and 74 references