Abstract: This comparative study on masonry works examines the potentials of interlocking masonry over the conventional masonry work. It seeks to highlight the merits of interlocking blocks as a better alternative towards achieving a sustainable low-income housing in Nigeria. The study investigates 20 randomly selected building projects in 4 out of the 6 geo-political zones in Nigeria as case studies. Data for the study were collected through observations and interview schedules administered to practicing professionals in the building industry (Architects, Engineers, Quantity Surveyors, Builders and Contractors) from selected cities in Nigeria. Variables investigated include: masonry setting time, gangs of labour engaged together cost with a view to measure time, labour and cost expended on the 2 types of masonries used in these projects. Results from the survey were analysed in collaboration with the Quantity Surveying Department, Federal University of Technology, Akure. Findings from the field signifies shorter time of construction, reduced number of labour and cost of construction expended if interlocking blocks are used in housing construction as compared with the use of conventional blocks. The study further recommends that the material should be used as a replacement to conventional types in construction of low-cost housing in Nigeria.