Residential quality has become a fundamental determinant of quality of life in urban settlements. The study aims to assess the impact of declining residential quality and quality of life in Yenagoa City, Nigeria. The objectives are to identify residential quality indicators of QoL used to assess these impacts of residential quality indicators on QoL and identify sustainable physical planning measures to improve residential quality and QoL of residents of the study area. The study adopted a quantitative research approach employing a descriptive research design. The study employed a simple random technique for the selection of 6 neighbourhoods. Three hundred ninety-six (396) respondents were obtained by applying the Taro Yamane formula at a 5% precision level and proportionately distributed across sampled neighbourhoods. The study found that the declining residential quality affects physical, social and economic domains of life as residents are living more in rooming housing and blocks of flats with an average of 4-6 households and 2-3 households, with mostly 4-6 persons per household occupying 2-3 rooms and 1 room. More than 60% of the buildings in the neighbourhoods needed more water supply and mainly had untarred access roads without drainages. The findings further showed that some neighbourhoods lacked secondary school facilities. The study found that the prevalence of crime and violence has caused injury, property loss and life in the study area. The study found that a substantial percentage of residents are unemployed, with the average earning of the employed being less than N60,000 monthly. The study revealed that the contributions of the indicators used for assessing demonstrated from the rating of perceived QoL of the neighbourhoods as “unsatisfactory” and “satisfactory”. However, to improve these conditions, the following measures are proffered including urban renewal schemes should be carried out in the neighbourhoods, government agencies involved in physical planning, development control and management should strictly enforce existing physical planning policies, regulations and standards, develop a Participatory Planning Approach (PPA) framework were members of the neighbourhoods and the city development agencies will collaborate in the decision-making process and halt urban sprawl and leapfrog development in the city to prevent informal settlements formation.
