The purpose of the presented research was to determine the effectiveness and sufficiency of measures put in place to protect the business continuity of critical infrastructure (CI) and key services (KSs) during the COVID-19 pandemic. The wide variety of research conducted in the area of business continuity maintenance during the COVID-19 pandemic does not change the fact that there is still a research gap in this area, particularly in terms of issues related to CI and KS protection. A systematic review of scientific publications revealed the need for continued research into this topic given the fact that only 19 papers related to CI continuity and 8 directly to KS operators could be identified. Holistic and interdisciplinary research is particularly needed to organize and systematize the existing scientific knowledge on the subject, and in practical terms, help organizations and institutions to better prepare for future continuity disruptions. A survey conducted between March and May 2021 among entities operating in Poland and classified as critical infrastructure operators as well as key service operators, subcontractors, and suppliers crucial to maintaining the continuity of critical infrastructure operations revealed that entrepreneurs, surprised by the speed and aggressive nature of the pandemic, mainly resorted to protective measures that were immediately available, standard solutions that did not require excessive financial and organizational effort. But in the face of long-term pandemic threat, such measures may no longer be sufficient, so it is important to intensify research into those precautions that require readaptation of work organization and organizational processes to protect key workers, increase supply chain resilience, and protect the work process.