Analysis of the effect of psychosocial factors and co-morbidities on the health status of patients with chronic nonspecific low back pain and patients with surgical intervention because of disk herniation was performed. One hundred and two nonselected consecutive inpatients with chronic nonspecific low back pain were included in the study. Their average age was 56.7 (SD = 10.9) years. The control group consisted of 199 subjects matched according to age and sex, chosen from the database of the national representative health survey Hungarostudy 2006, which involved 4,527 subjects. We measured quality of life including mental health with the SF-36 questionnaire validated for use in Hungary, the short 9-item version of the Beck Depression Inventory, the WHO-Five Well-Being Index, and the Hospital Anxiety-Depression Scale. We characterized the socio-demographic status with variables on age, sex, marital status, and education. Data on symptoms and signs of low back pain, other musculoskeletal diseases, and their treatments including spinal surgery were recorded. Co-morbidity and body mass index were considered as independent indicators of health. Depression as measured by Beck Depression Inventory and severity of depression did not vary significantly according to marital status, education, hypertension, diabetes, and gastrointestinal disease. Only half of the patients (52 %) were in the normal range of the scale; 22 % suffered from mild, 16 % from moderate, and 12 % from severe depression. Average values for anxiety and depression as measured by Hospital Anxiety-Depression Scale and Beck Depression Inventory were both significantly higher in the patient than in the control group (Hospital Anxiety Scale: p = 0.0001; Beck Depression Inventory: p = 0.0001). According to the WHO Well-Being Index-5 scale, the difference between patients and the control group was significant (p = 0.0001). Furthermore, correlation was found between the incidence of depression and surgery. Depression was demonstrated in 47.4 % of those patients who had no surgery, in 50 % of patients who had one round of surgery, and in 62.5 % of those who had undergone surgery more than once; the contingence coefficient was 0.211. According to different measurements, the psychological state of patients with chronic nonspecific low back pain was significantly altered as compared to the matched Hungarian population. Higher anxiety and depression markers occurred in 48 % of the patients. There was no correlation between the depression of patients with low back pain and variables such as marital status, education, and co-morbidities. Our study is the first to demonstrate that depression runs parallel with the number of surgical procedures. Therefore, if there is a relative indication for surgery, depression and severity of depression should be assessed and considered when deciding on the intervention.