Drilling oil and gas well at the lowest possible cost has always been paramount to drilling engineers in order to achieve their company’s objectives. However, in most cases, this is not attained because of the problem associated with the drilling bit selection, drilling design and drilling parameters. As it is a fact that the large chunk of the cost of bringing oil and gas to the surface is always incurred at the drilling/completion stage. In this study, data were gathered from selected 5 Niger Delta wells and were analyzed. These data were used to calculate the costs of drill bits and the bits with lowest costs. The drilling cost was studied and optimization procedure employed to select the best bit from well data obtained. Bits RSS1, RSS2, RSS3, RSS4, GX1 and BX1 that were used to drill, were select for this study. Drilling cost relation was to ascertain the most cost-effective one. Drilling with bit RSS1 showed the lowest cost possible, therefore RSS1 was said to be optimized. In consideration of the drill bit specific energy (SE) with respect to the ROP, RSSI showed a low value, indicating minimal energy requirement for the successful drilling operation. Conclusively, the SE is a function of ROP and ROP was highest at the minimum SE. Optimized where the drilling cost was minimum.