The utilization and development of water resources involve water quantity along with the significantly increasing aspect of quality which is generally defined by chemical, physical and biological variables. As any information on quality can only be achieved by monitoring the variables in the concerned river-basins, the major argument concentrates on the decision-making concerning the selection of variables among the hundreds of ones, since the measurement of all possible variables is practically not an achievable goal. This study attempts to evaluate the prevailing approaches and guideline statements in a systematic framework towards the determination of a methodological approach for the selection of the quality variables to be monitored in a river-basin monitoring network. The proposed approach necessitates the definition of monitoring objectives preceding the variable selection which is to be followed by further selection criteria to decrease the number of variables chosen formerly with respect to objectives. The water uses and impact assessment are considered to be the two common gross monitoring objectives of monitoring programs, where the water uses targets the beneficial uses of water by the public, while impact assessment targets the determination of the quality characteristics of point and non-point source discharges into the river-basins.