abstract The ability to effectively use any technology depends on how well it is understood. This condition becomes even more important with emerging technologies, as is Coiled Tubing Drilling (CTD). This paper will define the components of CTD as a "system" (Coiled Tubing Unit-Downhole Motor-Bit), and show that the understanding of the system and the ability to match its capability and needs is very important. It will show that properly engineered and selected PDC bits are effective on CTD and provide information on how seemingly minor changes on PDC bits affect their performance more than they do other types of bits. PDC bit development methodology and effectiveness will be discussed. It will describe how specialized PDC bits performed competitively within the operational constraints established by the system, and how the bits responded as analytically predicted. Finally, this paper will describe how a group effort which allowed the free flow of information between all the parties involved was successfully used on a PDC-CTD project.