Introduction: Out-of-hospital cardiac arrests (OHCAs) represent critical medical emergencies in which timely interventions can make a significant difference in patient outcomes. Despite their importance, the role of on-scene witnesses during such events remains relatively unexplored. Aim of the Study: This research seeks to shed light on the influence of witnesses, especially family members, during OHCAs and the effect of their interventions, or the absence thereof, on outcomes. Drawing from existing literature, our working hypothesis suggests that the presence of a witness, particularly one who is knowledgeable about CPR, can increase the likelihood of obtaining the return of spontaneous circulation (ROSC), potentially enhancing overall survival rates. Methods: Using a retrospective analytical method, we thoroughly reviewed medical records from the Lublin Voivodeship between 2014–2017. Out of 5111 events identified using ICD-10 diagnosis codes and ICD-9 medical procedure codes, 4361 cases specifically related to sudden cardiac arrest were chosen. Concurrently, 750 events were excluded based on predefined criteria. Results: Both basic and advanced EMS teams showed higher rates of CPR initiation and an increased likelihood of obtaining ROSC. Notably, the presence of a trained EMS professional as a witness significantly increased the chances of CPR initiation. The presenting rhythms most often detected were ventricular tachycardia (VT) and ventricular fibrillation (VF). Different urgency codes were directly linked to varying ROSC outcomes. When witnesses, especially family members, began chest compressions, the use of amiodarone was notably higher. A significant finding was that 46.85% of OHCA patients died without witnesses, while family members were present in 23.87% of cases. Actions taken by witnesses, especially chest compressions, generally extended the overall duration of patient care. Conclusion: The crucial influence of witnesses, particularly family members, on OHCA outcomes is evident. Therefore, it is essential to increase public awareness of CPR techniques and rapid intervention strategies to improve outcomes in emergency situations.