Objective Our purpose was to investigate the burnout syndrome through the comparison of different work settings within the health system. The survey concerns 100 healthcare workers, 50 working in resuscitation, post-surgery intensive care (ICU) and post-transplantation units ("critical area"), and 50 in general medicine, allergology, eye surgery, and ophthalmology departments ("treatment and diagnosis area"). The former area was considered as the Experimental Group, while the latter constituted the control group. Methods Observational study within the healthcare area, carried-out subjecting all 100 workers to test. All involved workers underwent two psychometric tests that were validated in Italy, i.e., the Maslach Burnout Inventory, that assesses the burnout syndrome, and the Defence Mechanism Inventory, focusing on defence mechanisms. On the basis of the scores on the Maslach Burnout Inventory, we classified the workers as Low/Medium/High burnout according to the three dimensions of the test, i.e., emotional exhaustion (<= 14; 15-23; >= 24), depersonalisation (<= 3; 4-9; >= 9), personal accomplishment (>= 37; 30-36; <= 29). Looking at the cut-off values as indicated on the Maslach Burnout Inventory test manual, we identified 36 workers with a critical burnout level, 17 within the "critical area" and 19 in the "treatment and diagnosis area". Working area (critical vs. treatment and diagnosis) and gender (men vs. women) were the independent variables, while answers on the defence mechanism questionnaire were the dependent variables. To rule-out the potential impact of working area and gender factors, we used the analysis of variance for independent factors, in terms of differences between principal effects mean and interaction. Data were analyzed using the statistic package software, SPSS. Results Among the 36 workers scoring high on burnout, those belonging to a critical area of work utilize defence mechanisms more often compared with those working in the treatment and diagnosis area. This is especially true regarding aggressiveness, where we found also an impact of gender, which interacted with "working area" (F1,32 = 4.01; p < 0.05), indicating that women working in ICUs are more likely to react with aggressiveness compared with the others subgroups (Fig. 1). The other two defence mechanism used more often by workers scoring high in burnout were projection and overturning. We did not find statistically significant differences regarding rationalization and turning to one self. Conclusions We can state that in a critical area like ICU, people scoring high on burnout tend to adopt defence mechanisms more than people in the "treatment and diagnosis area". This is probably due to the fact that the work environment of the latter category experience less emergency dynamics. These mechanisms mostly involve aggression, projection and overturning. Using more aggression mechanisms, crediting to someone else bad behaviour towards themselves in order to raise the level of self-esteem and tending to understate the seriousness of external or internal threats seems to be the typical behaviour of burned out subjects in the ICU area.