Environmental degradation is an increasing problem in many parts of the world and the type of ecology prevalent in an area plays a major factor that determines the extent of degradation. The study examines causes of environmental degradation in coastal areas of south west Nigeria. It was propelled by environmental challenges, and identified responsible factors in the study area. Environmental degradation is the major concept in this study and the DPSIR framework was used in understanding the concept. The study was carried out using primary and secondary sources of data collection. The main techniques for primary data collection were questionnaire survey and focus group discussions. Data were collected from one thousand, seven hundred and eighty-two (1,782) sampled respondents who are coastal dwellers that are involved in economic activities within the coastal areas. The FGD was conducted in 54 settlements with a minimum of 10 discussants which constitute a mix of the elderly men and women in all the sampled communities. Secondary data were obtained from National Population Commission (2006). Data were analysed using descriptive and inferential statistics as well as cartographic method, and the information from the FGD were analysed using a thematic approach. The study shows that waves breaking along the coastline are the main explanatory factors responsible for coastal erosion (84.0%). Flooding in the settlements where it occurs was mostly attributed to tidal rise/tidal waves (97.0%). Tidal wave was believed to be the major cause of water hyacinth (51.8%). Pollution is caused by a mixed factor of over development of coastal areas, migration to coastal areas, population growth and increased tourism. Soil infertility is caused mainly by sea water infiltration into farmlands especially when farmlands are located too close to coast lines (73%). Over development of the coastal area is mainly responsible for sand mining (67.0%). The study concludes that environmental influence remains strong in the coastal environment. Therefore, concerted community efforts are needed to provide leadership and modalities for the management of environmental challenges in coastal communities. Fundamentally, official attention should be geared towards reducing the rate at which the environment becomes degraded in the coastal communities.