Street trading is one of the misuses plaguing the public open spaces in third-world cities. The effects of the activity on accessibility in city centres have transformed them into contested places for incompatible functions. The aim of this study is to analyze the characteristics of street trading and its implications on urban open spaces vis-a-vis the landscape and accessibility in the city centre. Purposive sampling of 12 streets and their streetscapes that are mostly used for informal trading in Osogbo were investigated. Total sample size of 180 informal traders was randomly selected from the streets to elicit necessary information on their activities. A descriptive analysis of the data collected through physical observation and questionnaire survey was carried out. The results show that the activity has serious negative impacts on accessibility, erection of illegal structures, traffic congestion, solid waste generation, auto-accidents and deface of urban aesthetics. Control option favours inclusive principles of postmodernism in the landscape design of streets and streetscapes as public infrastructure. The study concludes with recommendations on urban renewal strategies to ameliorate street trading in Osogbo and approach that could be adopted in other cities of developing countries at large.