A quantitative research approach and quasi experimental research design with pre and posttest without control group was undertaken on 500 substance abusers selected by purposive sampling technique in de-addiction center of M.H.I, S.C.B medical college hospital, Cuttuck, Odisha to assess the effectiveness of yoga therapy on substance abuse among the substance abusers. Data were collected through structured interview schedule and collected data were analyzed by using descriptive and inferential statistics. Highly significant (P<0.01) difference was found between pre and posttest knowledge scores and no significant (P>0.05) association was found between knowledge scores in relation to demographic variables of substance abuser