This paper depicts the findings of the survey research covering 65 engineering institutions which are recognised as research centres in the state of Karnataka, India. Responses have been sought from research supervisors and research scholars as to the extent of the use of obsolete grey collections. Opinions have also been captured from the chief librarians of the 65 research institutions as regards the ways of managing the obsolete grey literature. The following are the areas covered in the study in respect of obsolete grey resources available in these 65 research libraries. ⢠Demand for GL in engineering sciences and technology ⢠Grey Literature collection in English and Foreign languages ⢠Process of weeding-out of obsolete grey literature ⢠Reasons for weeding out of old GL collections ⢠Extent of the use of old GL collections ⢠Weeding-out vis-A -vis Relegation of obsolete GL collections. The study was undertaken during 2007-2010 with the objective of understanding the pattern of obsolescence and the method followed in the libraries to manage the old GL collections in the engineering research institutions. The findings also project the practical methods followed by various libraries as to the weeding out process. Importance of old collections of GL for research vis-A -vis weeding out process adopted by the libraries have been depicted in the study based on the opinions exposed by 1270 researchers, which account for 84.6 of the total population. The summary or core of findings eventually shows that 66.4 of the research supervisors and research scholars hold the view that old collection of GL is of vital source for their research and has to be retained along with active collection in the libraries.