One of the early objectives of high-density low-cost flat housing is to overcome the squatter problems in urban areas such as Kuala Lumpur. As the country progresses towards being a developed nation, the quality and standard of living of its people have also improved. The low-cost flat housing initiative has also gone through changes to provide better living quality. This paper discusses the occupants’ satisfaction perception of outdoor environmental quality (OEQ) of a selected high-density low-cost flat housing located in the state of Selangor in Malaysia. The objective of the paper is to obtain the level of perception by the occupants of low-cost flats on the OEQ. The methodologies used in this study are site observation and questionnaire survey. This study found that the OEQ in the low-cost flat has generally fulfilled five out of 6 elements of OEQ. The only element that found to have poor perception is the level of safety.