Introduction: Primary immunodeficiencies (PID) are genetic defects of the immune system that result in chronic, serious, and often life-threatening infections if they are not diagnosed and treated. Worldwide, from 70 to 90% of PID sufferers remain undiagnosed because of poor awareness. Early diagnosis is very important for adequate prevention and management of PID infectious complications and may improve the life quality of patients with PID. Aim of the study: The aim of this study was to assess the awareness of physicians of different specialties about the signs of primary immunodeficiency in children and adults. Material and methods: A survey among physicians of different specialties on awareness of PID was conducted. The study involved physicians of the Ternopil region of Ukraine. Of 103 participants 42 were paediatricians, 25 general practitioners/family physicians, eight internists, 13 paediatric surgical specialists, and 15 physicians of paediatric sub-specialties. The survey consisted of a questionnaire containing 25 questions. Results: Sixty-one (59.2%) physicians gave more than 50% of correct answers. The percentage of correct answers to the questions about warning signs of PID in children was 66.1% among paediatricians and 64% among general practitioners, in adults-66.7% and 72%, respectively. The lowest knowledge of PID was about the specific signs of PID, more often concerning verification of Nijmegen breakage syndrome, ataxia-telangiectasia, and DiGeorge syndrome. Conclusions: This study has revealed poor awareness about PID among physicians in the Ternopil region of Ukraine. There was no significant difference in the percentages of correct answers among the first-contact physicians (paediatricians, general practitioners/family physicians) and paediatric sub-specialists. There is a significant need for educational programs to improve physicians' knowledge on PID. Implementation of the model of combined physician education and public awareness may improve detection of PID in children in the early stages.