The Yoruba and the Hausa are among the largest, politically active and commercially inclined ethnic groups in Nigeria. While the Hausa live in the north of the country, the Yoruba dwell in the south western part. The trade in cattle and kola nuts brought many Hausa to settle in the Remo-Yoruba town of Sagamu. Over the years, this trade became an avenue for both ethnic groups to develop a cordial and harmonious relationship until the crisis of July 1999 broke out, bringing about a far reaching impact not only on the town of Sagamu but also on the hitherto existing peaceful relationship between the two ethnic groups. Indeed, some of the effects of the conflict have remained till today. This paper is an historical analysis of the Hausa/Yoruba conflict. It examines the causes of the conflict and discusses its character and nature. Unlike previous studies on the subject of conflict and ethnicity, this paper brings out the central importance of culture in the inter-relationship between two ethnic groups in Nigeria. It shows that the failure to respect the culture of one ethnic group by the other was the root cause of the Yoruba/Hausa conflict.