Basically, since the main purpose of every library is to collect, organize, preserve, conserve and provide knowledge and information materials available to users, hence the researchers decides to examined and understudy the trends in collection development department and how information resources are preserved in Lagos State University Library, Ojo-Lagos. This study revealed that the collection development in library helps in conserving information resources in order to reflect the library mission which is collect, organize, preserve, conserve. Also, this study recommended that policies in collection development should be given serious consideration in the building library collections. Therefore, there is need for tertiary institutions especially Lagos State University to provide adequate funding for resources and maintain a good and up-to-date maintenance ethics for better preservation and conservation of the information resources.