Alcohol was involved in 63.8% of all self harm cases on the pilot register
Alcohol was involved in nearly two thirds of self harm cases which were recorded as part of a pilot programme in the Western Health Trust area.
The "Registry of Deliberate Self Harm" recorded almost 2,700 incidents between January 2007 and December 2008.
The A&E units of Altnagelvin, Tyrone County and Erne Hospitals took part.
The Health Minister Michael McGimpsey said it was "particularly worrying that alcohol is reported as a contributing factor in a large number of the cases".
The pilot programme is part of the Northern Ireland Suicide Prevention Strategy and will now be extended to Belfast.
The figures, which cover the registry's first two years in existence, also showed that one in every four incidents of self harm recorded in the Western Trust in 2007 had been carried out by patients who had already been treated for self harm that year.
By 2008, the repeat attendance figure had reduced to one in five (20.8%).
The highest rates of self-harm were among women aged between 35 and 44 years old and men in the 25-34 age group.
The registry's first report also said that patients were more likely to need treatment for self harm at weekends.
Alcohol was not the "main method of self-harm" but featured as a "major contributing factor" and was involved in 63.8% of all cases.
There was also a 10% increase in the number of self harm cases involving alcohol from 2007 to 2008.
Mr McGimpsey said addressing the issue of alcohol misuse continued to be "a key priority" for his Department.
He added the report provided "a greater understanding of deliberate self-harm" and would help health and social care professionals in planning their response to those at risk.