There has been a substantial increase in Multimorbidity, worldwide. Extensive empirical research has found that General Practitioners (GPs) often feel overwhelmed when dealing with such patients . While clinical decision support systems (CDSS) are effective at reducing clinical decision errors and improving healthcare processes across diverse settings , the use of CDSS within multimorbidity care is under investigated. This study employs a multi-method approach to examine how well CDSS currently support Irish GPs when dealing with multimorbid patients. The findings uncover a number of inadequacies, including: a lack of provision of integrated medical guidelines for multiple chronic diseases within current CDSS; and an inability to centralise the patient rather than the disease using such systems. This research underlines the need for further research into CDSS for multimorbidity and highlights key issues that must be addressed in order to improve how CDSS support the care of multimorbid patients.