Load Management (LM) is an optimization problem which constrained by time of electricity use, peak demand, minimum load and electricity tariffs. The general objective of this research is to study the subject of LM techniques, especially rescheduling the load or part of it to other periods of the day and time of use (TOU) pricing on real industrial plant to evaluate the benefits of applying such management techniques. This thesis will focus on the development of two mathematical models for different types of end users.   These models will enable the utility planner to design a DSM in which demand, time and electricity prices will be used as the control variable of an objective function representing the target of the DSM program. The amount of energy, cost and time of use will reflect the state variables of the system. The first model is a DSM priority selection technique and the second model is an optimal tariff formulation. The applications of peak clipping, valley filling, load shifting, energy conservation and load building programs will be studied and evaluated.