Yoruba, is just one among the over 400 languages that are spoken in post colonial Nigeria. Among these languages is English, generally perceived as the language of education, government, mass media, administration, science and technology, prestige, wider national and international communication. English more than any other language has found its way into every Yoruba home and influences the Yoruba performance. What one notices is that the average Yoruba speaker switches from one language to another mainly English and to some extent pidgin and even other Nigerian ethnic languages. The resultant linguistic choices manifest describable underlying grammar and generate questions about sociolinguistic and psycholinguistic motivations for code-mixing. This phenomenon is most common in the urban cities perceived as melting pots of succour with its centrifugal pull of multicultures, peoples and needs. Urbanity exerts linguistic pressure on speakers of Yoruba who must adjust to a host of communication exigencies, roles and contacts that tend to dismount homogenous cultural and linguistic boarders. The fact is that code- mixing may not be a linguistic aberation, but it has potency for linguistic empowerment or endangerment of the receiving superstrate language and the culture of its users. This study will examine the phenomenon of code-mixing among Yoruba speaking “Lagosians”, analyze the linguistic pattern and motivation and articulate its implication towards sustaining a homogenous Yoruba society and identity.