Aim. The aim of this research is to present the severity of the generalized anxiety disorder (GAD) symptoms and its correlation with neuroticism among patients suffering from somatic diseases. Methods. 184 subjects participated in the study: 45 inpatients undergoing haematoiogical treatment (group 1), 46 inpatients from the internal ward (group 2), 48 patients infected with HCV prior to treatment (group 3) and 45 healthy persons from the control group (group 4). The patients' level of generalized anxiety was measured by means of the Present State Examination Questionnaire (PSE), whereas the level of neuroticism was measured by means of Eysenck's Personality Questionnaire (EPQ-R). Results. The GAD was found to affect more patients with somatic diseases than people from the control group (group 1: 11%, 2: 8.7%, 3: 8.7% and 4: 6.7%). 14 out of 16 persons with GAD had the neuroticism value above median. Median scores of neuroticism were similar in all groups except for the control group in which the median value was slightly lower. The correlation between the level of neuroticism and the increase of generalized anxiety symptoms did not depend on the gravity of the somatic diseases. The value of correlation was found to be the highest among patients infected with HCV (0.73) and lower in the remaining two groups (0.54 and 0.58). The increase of generalized anxiety symptoms was proportional to the level of neuroticism, the regression line slope depended on subjective evaluation of gravity of the diseases. The regression line slope was found to be the highest amongst haematologically treated patients (1.54), smaller among patients from the general practice ward (0.84) and those infected with HCV (1.04), and the smallest among patients from the control group (0.15). Conclusions. Patients suffering from internal illnesses are much more vulnerable to GAD and have a higher level of GAD symptoms, especially ones with an elevated level of neuroticism. The regression line slope between GAD scores and neuroticism scores can be understood as an indicator of psychological stress.