The present invention relates to methods of identifying a disease treatable with PARP modulators by identifying a level of PARP in a plurality of samples from a population, making a decision regarding identifying the disease treatable by the PARP modulators wherein the decision is made based on the level of PARP. The method further comprises of treating the disease in a subject population with the PARP modulators. The methods relate to identifying up-regulated PARP in a disease and making a decision regarding the treatment of the disease with PARP inhibitors. The extent of PARP up-regulation in a disease can also help in determining the efficacy of the treatment with PARP inhibitors. The present invention discloses various diseases that have up-regulated or down-regulated PARP and can be treated with PARP inhibitors or PARP activators, respectively. The examples of the diseases include cancer, inflammation, metabolic disease, CVS disease, CNS disease, disorder of hematolymphoid system, disorder of endocrine and neuroendocrine, disorder of urinary tract, disorder of respiratory system, disorder of female reproductive system, and disorder of male reproductive system.