Ca2+ is a crucial second messenger with response to wide variety of environmental stresses and development process. Out of three Ca2+ sensor gene families, two gene families (CBL and CaM) which act as sensor relays were selected for the study. The drought responsive members in CaM (Calmodulin) (LOC_Os03g20370) and CBL (Calcineurin B–like) (LOC_Os03g42840, LOC_Os05g45810, LOC_Os01g51420) were used for identifying their homologous genes in maize, sorghum and Arabidopsis. A total of 34 genes from the four species were analyzed for their phylogenetic relationship, gene structure, cisregulatory elements and expression level up on drought stress. Based on the comparative analysis, it was observed that all the identified homologous genes are potential for drought response which will be promising to the plant improvement programs. Further, rice calmodulin-1 was modeled by using the experimentally proven structure of homolog Arabidopsis calmodulin7 and the native like structure was obtained through conformational sampling analysis.