This study intended at investigation of relation between Biochemical Oxygen Demand and Chemical Oxygen Demand of Bahir Dar Textile and Bahir Dar Tannery industries wastewater treatment plant. Beside this, the study had characterized other selected parameters such as temperature (Tº), pH, total dissolved solids (TDS), dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), chloride (Cl-), sulphate (SO42+), sodium (Na+) and electrical conductance (EC) of industries wastewater treatment plant influent and effluent, the degree of the effluents biodegradability were obtained. In order to accomplish the objectives, the researcher reviewed some literatures related with this topic and the wastewater samples were collected from Bahir Dar Textile and Bahir Dar Tannery industries WWTPs influent and effluent sampling site using grab sample collection method. The correlation analyses were carried out using IBM SPSS Statically Analysis model based on the input-output data of their wastewater treatment plant. This study investigated that BOD5 correlates positively with COD of the treated effluent from both Bahir Dar Textile and Bahir Dar Tannery Industries. But those industries wastewater treatment plant influent degree of biodegradability were poor (< 0.3).