During the state of alarm declared in Spain by COVID-19 due to the pandemic, the country's authorities declared Social Services and their workers to be essential, considering that the activity of these professionals with the vulnerable population was crucial and that services should continue to be provided to guarantee the well-being of users in this exceptionally serious situation. This article analyzes the impact that the COVID-19 and the state of alarm has had on Spanish social service professionals. An ad hoc questionnaire was used, administered on-line, individually, voluntarily and anonymously to 560 professionals working in social services, both in the public and private sectors, based throughout Spain. This questionnaire has five different parts: socio-demographic profiling, impact that the health crisis has had on the practice of professional functions, degree of knowledge of the measures imposed to guarantee the protection and safety of professionals and users, impact that it has had on the professional and personal development of social services professionals and, the fifth and last part, degree of adaptation of the measures aimed at the care of the vulnerable population. These results are discussed based on the situation in which professionals working in this sector find themselves in the face of the changes they are experiencing in the development of their work, and we are able to determine the profile of the workers who have felt most affected by the situation, with the consequent and foreseeable mental and emotional affectation that this implies. These professionals tend to value more negatively the set of measures developed to mitigate the impact of COVID-19 on Spanish social services.