Mechanical workshops are considered as important buildings in faculty of engineering. Thermal comfort is an essential requirement in most occupied spaces because it affects the productivity, health and thermal satisfaction of the occupants. Natural ventilation, which may provide occupants with good indoor thermal comfort, and reduce energy costs, has become an important sustainable strategy in building designs. This article presents the results of a field measurement study conducted on the mechanical workshop building located in Faculty of Engineering, University of Aden, Yemen. The measurements were recorded within duration of one year, starting from October 2021 to September 2022. The measured values were then compared to the corresponding limit as specified in the ASHRAE Standard-55. It was found that the inside temperature at the selected locations of the mechanical workshop building exceed the respective upper limits as recommended in the ASHRAE Standard-55, showing that the existing air ventilation method is not able to provide an adequate level of thermal comfort to the occupants.