This paper discusses the potential of passive cooling techniques for Malaysian modern houses with the aim of reducing air-conditioning usage. A full-scale field experiment was carried out to reveal the detailed indoor thermal environment for various ventilation strategies. Night ventilation was found to be better than daytime ventilation, full-day ventilation and no ventilation in terms of air temperature reductions during the day and night. Night ventilation improves thermal comfort more than the other ventilation conditions based on operative temperature. However, further measures to lower indoor humidity, such as by dehumidification, or to increase indoor air velocity, such as by the use of a fan, are required to improve the thermal condition in the night ventilated room, especially in the daytime. In fact, the peak standard effective temperature (SET*) in the night ventilated room was decreased by 4.0°C mainly through the use of a ceiling fan. Thus night ventilation, with the use of a ceiling fan, was considered to be the superior option to the other conditions when the evaporative heat loss is taken into account in SET*. Several other potential passive cooling techniques are also proposed for achieving acceptable thermal comfort in modern Malaysian houses.