Research shows the increasing part the Clinical Nurse Specialist (CNS) plays in healthcare today. But what does a CNS actually do in their day-to day-work? This study, set in the Republic of Ireland, aimed to explore the CNS and clinical midwife specialist (CMS) roles in practice. Quantitative methodology was used to explore the roles and activities of the CNS and CMS. Following ethics approval, a valid and reliable questionnaire was circulated to the total population of CNS/ CMS in Ireland. The data were analysed using SPSS. This study articulates the individual role elements and activity level. The findings show the CNS/CMS to be active in the roles of researcher, educator, communicator, change agent, leader and clinical specialist, but the level of activity varies between different roles and individual role elements. The CNS/CMS is seen as a valuable resource in health care today and has potential to have a positive effect on patient care. The majority of CNS/CMSs are active in varying roles but the analysis shows lesser activity in some areas, such as research. The findings merit further study on role activity and possible variables that influence role activity.