Introduction: Survival rates from out-of-hospital cardiac arrest significantly improve when high-quality cardiopulmonary resuscitation (CPR) is performed. Despite sudden cardiac arrest being a leading cause of death in many parts of the world, no studies have determined the quality of CPR delivery by Emergency Medical Services (EMS) personnel in South Africa. The aim of this study was to determine the quality of CPR provision by EMS staff in a simulated setting. Methods: A descriptive study design was used to determine competency of CPR among intermediate-qualified EMS personnel. Theoretical knowledge was determined using a multiple-choice questionnaire, and psychomotor skills were video-recorded then assessed by independent reviewers. Correlational and regression analysis were used to determine the effect of demographic information on knowledge and skills. Results: Overall competency of CPR among participants (n = 114) was poor: median knowledge was 50%; median skill 33%. Only 25% of the items tested showed that participants applied relevant knowledge to the equivalent skill, and the nature and strength of knowledge influencing skills was small. Demographic factors that significantly influenced both knowledge and skill were the sector of employment, the guidelines EMS personnel were trained to, age, experience, and the location of training. Conclusion: Overall knowledge and skill performance was below standard. This study suggests that theoretical knowledge has a small but notable role to play on some components of skill performance. Demographic variables that affected both knowledge and skill may be used to improve training and the overall quality of Basic Life Support CPR delivery by EMS personnel.