Since the beginning of the COVID-19 pandemic in Spain, members of the State Security Forces and the Armed Forces have been mobilized to guarantee the security and mobility of the population and to support health institutions by providing personnel for care, creating field hospitals, transferring the sick and the dead, etc. The objective of this study was to determine the levels of burnout in these professionals using the Maslach Burnout Inventory (MBI) scale, both in its different subscales and its total value. The study was developed using a quantitative methodology through a simple random sample (n = 2182). An ad hoc questionnaire was administered including variables related to: (a) socio-demographic issues, (b) subjective perceptions about their working conditions and the need for psychological and psychiatric treatment, and (c) the Death Anxiety Scale developed by Collett–Lester, and the MBI. The results show high levels of burnout (28.5%) in all its subscales: emotional exhaustion (53.8%), depersonalization (58.0%), and lack of personal development (46.3%). The logistic regression verifies a series of predictive variables that coincide in each of the subscales. These data indicate the need to implement prevention and treatment measures for workers so that their, stress, and anxiety to which they are subjected during their professional activity does not become a norm that can have negative repercussions for them, especially given the risk of new pandemic waves.