The indoor climate in commercial kitchens is often unsatisfactory and the working conditions can have a significant effect on employees’ comfort and productivity. The differences between type (fast food, dining, etc.) and climatic zone can have an influence on the environment conditions and on the employees´ perception of kitchens thermal conditions. Moreover, size and arrangement of the kitchen zones, appliances, etc., complicate further an evaluation of the indoor thermal environment in kitchens. The on field physical measurements together with the occupants´ feedback is the effective way of defining the values of thermal comfort parameters in kitchens. It can also help to evaluate if the standardized methods are applicable for such non-uniform environment, like commercial kitchens. By using an established method and procedure for evaluating the indoor thermal comfort in commercial kitchens more than 100 kitchens environments in the United States were investigated in summer and winter. Results show the influence due to type of kitchen (fast food, casual, etc.) and climatic region. Physical measurement confirmed that communally the workers are exposed to a warm or hot environment, with temperature even higher than the ones that can be supported by the human physical strength. PMV/PPD index resulted not suitable for application in commercial kitchens. Kitchens environments with a big range of operative temperature were investigated.