Background: Research suggests that patients presenting to hospital with self-cutting differ from those with intentional overdose in demographic and clinical characteristics. However, large-scale national studies comparing self-cutting patients with those using other self-harm methods are lacking. We aimed to compare hospital-treated self-cutting and intentional overdose, to examine the role of gender in moderating these differences, and examine the characteristics and outcomes of those patients presenting with combined self-cutting and overdose. Methods: Between 2003 and 2010, the Irish National Registry of Deliberate Self-Harm recorded 42,585 self-harm presentations to Irish hospital emergency departments meeting the study inclusion criteria. Data were obtained on demographic and clinical characteristics by independent data registration officers. Results: Compared with overdose only, involvement of self-cutting (with or without overdose) was significantly more common in males than females, with an overrepresentation of males aged < 35 years. Independent of gender, involvement of self-cutting (with or without overdose) was significantly associated with younger age, city residence, repetition within 30 days and repetition within a year (females only). Factors associated with self-cutting as the sole method were no fixed abode/living in an institution, presenting outside 9 a.m. to 5 p.m., not consuming alcohol and repetition between 31 days and 1 year (males only). Conclusion: The demographic and clinical differences between self-harm patients underline the presence of different subgroups with implications for service provision and prevention of repeated self-harm. Given the relationship between self-cutting and subsequent repetition, service providers need to ensure that adequate follow-up arrangements and supports are in place for the patient.