Efforts to limit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among hospital healthcare staff are crucial for controlling the Coronavirus Disease 19 (COVID-19) pandemics. The study aimed to explore the prevalence and clinical presentations of COVID-19 in healthcare workers (HCWs) at the University Clinical Hospital (UCH) in Wroclaw with 1677 beds. The retrospective study was performed in 2020 using a self-derived structured questionnaire in a sample of HCWs who were diagnosed with SARS-CoV-2 infection confirmed using a PCR double gene test and consented to be enrolled into the study. The significance level for all statistical tests was set to 0.05. The study showed that of the 4998 hospital workers, among 356 cases reported as COVID-19 infected, 70 consented to take part in the survey: nurses (48.5%), doctors (17.1%), HCWs with patient contact (10.0%), other HCWs without patient contact (7.1%), and cleaning personnel (5.7%). HCWs reported concurrent diseases such as hypertension (17.1%), bronchial asthma (5.7%), and diabetes (5.7%). Failure to keep 2 m distancing during contact (65.5%) and close contact with the infected person 14 days before the onset of symptoms or collection of biological material (58.6%) were identified as the increased risks of infection. A large part of infections in hospital healthcare staff were symptomatic (42.9%). The first symptoms of COVID-19 were general weakness (42.9%), poor mental condition (41.4%), and muscle pain (32.9%); whereas in the later stages of the illness, general weakness (38.6%), coughing (34.3%), lack of appetite (31.4%), and loss of taste (31.4%) were observed. In about 30% of the infected HCWs, there was no COVID-19 symptoms whatsoever. The vast majority of the patients were treated at home (85.7%). In conclusion, the majority of the SARS-CoV-2 infections in the hospital HCWs were asymptomatic or mildly symptomatic. Therefore, successful limitation of COVID-19 infection spread at hospitals requires a close attention to future cross-infections.