Engine stop/start and cylinder deactivation are increasingly in use to improve fuel consumption of internal combustion engine in passenger cars. The stop/start technology switches off the engine to whenever the vehicle is at a stand-still, typically in a highly-congested area of an urban driving. The inherent issue with the implementation of stop/start technology in Southeast Asia, with tropical climate such as Malaysia, is the constant demand for the air-conditioning system. This inevitably reduces the duration of engine switch-off when the vehicle at stop and consequently nullifying the benefit of the stop/start system. On the other hand, cylinder deactivation technology improves the fuel consumption at certain conditions during low to medium vehicle speeds, when the engine is at part load operation only. This study evaluates the fuel economy benefit between the stop/start and cylinder deactivation technologies for the actual Kuala Lumpur urban driving conditions in Malaysia. Malaysia is chosen as a case study to represent a typical urban environment in Southeast Asia. A 1.6 L PFI 4-cylinder engine is modeled in one-dimensional gas dynamics software to predict the fuel consumption. A transient driving profile obtained from the actual road test over the Kuala Lumpur route is simulated and the fuel consumption is compared with New European Drive Cycle (NEDC). The results provide useful insight and enable manufacturers to assess and consider which of the two technologies offers more impact on the fuel economy and the challenges under urban driving in Southeast Asia conditions.