The present study is exhibited the preservation and conservation techniques in the college libraries of Diamond Harbour and Alipore subdivisions in the district of South 24parganas. It is also discusses about degradation problems of print and non-print materials, causes of deterioration of library documents and different obstacles to use preservation techniques. To secure the library materials in a well manner need to apply the preservation and conservation techniques which includes cleaning and dusting, use of insecticides and insect repellent such as Thymol, Dichlorovos, Dursban, Naphthalene balls, Neem leaf etc., besides that there is a provision for security systems of the college libraries to secure the library materials, mutilation and defacing of paper-based materials and shelving library documents to allow for free flow of air. But binding, photocopying, and use of insecticide and insect repellent for preservation are used occasionally. Hence, the results indicate that the different college libraries are more or less need to preserve their library documents according to the existing preservation policy as well as new preservation policy, and also college authorities should provide sufficient funds and engage skilled laborers.