Purpose: One of the reasons for postgraduate trainees not to choose working in a rural area is uncertainty related to the lack of competencies. The aim of this study was to investigate the concept of uncertainty by measuring competencies and to examine the psychometric properties of an instrument that measures competencies related to uncertainty in the self-assessment of postgraduate trainees in family medicine. Patients and Methods: A questionnaire was created based on pre-existing instruments. It was distributed to participants of postgraduate training seminars in the federal states of Baden-Württemberg and Schleswig-Holstein, Germany in 2016. Descriptive statistics and a partial correlation analysis were calculated for measuring the degree of association between year of postgraduate training and items’ responses. Psychometric properties were assessed by calculating descriptive item analysis, factor analysis and internal consistency. Results: The response rate was 85% (105/124). More than one-fifth of the participants stated to show only seldom or sometimes the following skills: ability to balance work and life (N=25, 24%), letting a mild disorder run its own way (N=24, 23%) and ability to conduct interventions that decreased aggression from the patient (N=22, 21%). More than half of the participants felt (very) insecure in performing routine child check-ups, the application of a below elbow backslab and the partial removal of a toenail. Nine out of 21 items showed positive statistically significant correlation between level of competence and progress in training. Factor analysis led to a final instrument with 12 items (Cronbach’s α=0.736) and a three-factor-structure: “doctor well-being and resilience”, “communication” and “skills”. Conclusion: In order to reduce uncertainty with all its consequences, a focus on teaching of competencies regarding the physicians’ well-being and resilience, communication and skills has to be continued in postgraduate training.