Occupational exposure to smoke from commercial kitchens such as steakhouses may be associated with an increase in the prevalence of respiratory symptoms and an acute reversible decrease in pulmonary functional capacity, and exposure to coal smoke is a risk factor for the development of respiratory diseases. The objetive of study was evaluate the levels of exhaled carbon monoxide (COex) and carboxyhemoglobin (COHb) in steakhouse workers. This is an observational, longitudinal and prospective study in the city of Cuiabá, Mato Grosso, Brazil. The total of 29 professionals working in steakhouses participated in the study. Data on socio-demographic characteristics, work environment characteristics, life habits and respiratory symptoms were extracted from questionnaires. COex and COHb levels were measured before exposure and every hour up to a 4 hour exposure period. Twenty-nine workers participated, with a predominance of females (55.2%), with a mean age of 36.40±11.49 years. It was observed that 18 (62%) of the workers had respiratory symptoms. COex and COHb levels were elevated after 4 hour exposure (p<0.05), but within acceptable parameters. COex and COHb levels are elevated in a short period of time to occupational exposure to steakhouse activities.