In the past few decade researches have developed their EOQ models under constant deterioration and constant demand. However, it is not true in actual practice. In this paper, we have established inventory model with exponential time-dependent demand and time- dependent time-dependent deterioration. Shortages are allowed. The demand rate and unit production cost both are considered as proportional to each other. Mathematical formulation is developed considering two different models that is Model 1: Inventory model without shortages and Model 2: Inventory model with shortages. Numerical examples are provided for both the models. Sensitivity analysis is provided to study effect of different parameters on total average cost for inventory system.