Objectives: The purpose of this study was to determine airborne bioaerosols such as bacteria and fungi in the kitchens of restaurants, and to assess the effects of thermal factors on the levels of the bioaerosols. Methods: Air samples were taken from kitchens of nine restaurants. An Anderson type air sampler was used for sampling and measurements. Petri dishes filled with a microbiological culture medium (trypticase soy agar for bacteria and Sabouraud dextrose agar for fungi) were used as the sampling surface. Results: The levels of bacterial aerosol measured were $10-10^3CFU/m^3$ and fungal aerosol $10-10^2CFU/m^3$, respectively The mean values of air temperature and relative humidity in the kitchens were $24.6^{circ}C$ and 46.4%, respectively. Overall, the levels of bacterial aerosol varied by the restaurant type, and fungal aerosol by the business period (p < 0.05). The main effect of air temperature and interaction effect of air temperature and relative humidity onto the bacterial level were significant (p < 0.05), whereas the effects were not significant onto the fungal level. Conclusions: The results indicate a wide variation in the levels of bioaerosols among different kitchens. The observed differences in bioaerosol levels in the kitchens reflect different periods of use. The interactions of air temperature and relative humidity onto the bacterial level suggest that constant attention should be paid to avoid peaks of contamination during the summer season.