Operating theatres require an intensification of disinfection processes, and consequently a massive use of disinfectants. The aims of this study were to detect occupational dermatoses among instrument technicians, to assess the chemical risk associated with the use of disinfectants in operating theatres, and to propose appropriate preventive measures. Our study was a descriptive cross-sectional study carried out in the operating theatre of CHU Habib Bourguiba and the gynaecology theatre of CHU Hédi Chaker in Sfax, Tunisia, involving 45 instrument technicians. According to Mathias' criteria, the diagnosis of occupational dermatosis was retained in 31.1% of instrument technicians, with irritant contact dermatitis (10 cases), allergic contact dermatitis (2 cases) and urticaria (2 cases).The application of the occupational risk assessment guide enabled us to identify the hazardous situations associated with each disinfectant, to estimate the severity of potential damage for each hazardous situation, to conclude on the priority for action, to assess the level of protection and to propose preventive measures adapted to each risk.