This thesis investigated whether out­come after in-hospital cardiac arrest patients could be improved by a cardiopulmonary resuscitation (CPR) educational intervention focusing on all hospital healthcare professionals. Annually in Sweden, approximately 3000 in-hospital patients suffer a cardiac arrest in which CPR is attempted, and which 900 will survive. The thesis is based on five papers: Paper I was a methodological study concluding in a reliable multiple choice questionnaire (MCQ) aimed at measuring CPR knowledge. Paper II was an intervention study. The intervention consisted of educating 3144 healthcare professionals in CPR. The MCQ from Paper I was answered by the healthcare professionals both before (82% response rate) and after (98% response rate) education. Theoretical knowledge improved in all the different groups of healthcare professionals after the intervention. Paper III was an observational laboratory study investigating the practical CPR skills of 74 healthcare professionals’. Willingness to use an automated external defibrillator (AED) improved generally after educa­tion, and there were no major differences in CPR skills between the different healthcare professions. Paper IV investigated, by use of a questionnaire, the attitudes to CPR of 2152 healthcare professionals (82% response rate). A majority of healthcare professionals reported a positive attitude to resuscitation. Paper V was a register study of patients suffering from cardiac arrest. The intervention tended not to reduce the delay to start of treatment or to increase overall survival. However, our results suggested indirect signs of an improved cerebral function among survivors. In conclusion, CPR education and the introduction of AEDs in-hospital – improved healthcare professionals knowledge, skills, and attitudes – did not improve patients’ survival to hospital discharge, but the functional status among survivors improved.