MLFB Neural network model by back propagation algorithm is one of the most significant methods in artificial neural network. MLFB model have been used in many areas of medical application. This paper describes the regimens specification for the HIV/AIDs patient�s based on the patients unique factors like age, weight, HB, CD4, CD8 . Using this MLFB back propagation algorithm, the regimens specification for the patient is calculated and to approximately predict, how long the patient can prolong his/her life with this regimens. This model is trained with 200 Patient�s medical information as input and regimens are the weight of the network. This network is adjusted with the threshold 0.001, so that it minimizes the error. The mapping and adjustment are continuing until all mapping example from the training set are learned.