The International Classification of Diseases-10 (ICD-10 is a new system that is expected to be implemented effective on October 1, 2013. This new system is a federally mandated change affecting all payers and providers, and is expected to exceed both the Health Insurance Portability and Accountability Act (HIPAA) and Y2K in terms of costs and risks. However, the Administration is poised to implement these changes at a rapid pace which could be problematic for health care in the United States. In 2003, HIPAA named ICD-9 as the code set for supporting diagnoses and procedures in electronic administrative transactions. However, on January 16, 2009, the Department of Health and Human Services (HHS) published a regulation requiring the replacement of ICD-9 with ICD-10 as of October 1, 2013. While ICD-9 and 10 have a similar type of hierarchy in their structures, the ICD-10 is more complex and incorporates numerous changes. Overall, ICD-10 contains over 141,000 codes, a whopping 712% increase over the less than 20,000 codes in ICD-9, creating enormous complexities, confusion, and expense. Multiple published statistics illustrate that there are approximately 119 instances where a single ICD-9 code can map to more than 100 distinct ICD-10 codes, whereas there are 255 instances where a single ICD-9 code can map to more than 50 ICD-10 codes. To add to the confusion, there are 3,684 instances in the mapping for diseases where a single ICD-10 code can map to more than one ICD-9 code. Proponents of the new ICD-10 system argue that the granularity should lead to improvements in the quality of health care, since more precise coding that more accurately reflects actual patient conditions will permit smarter and more effective disease management in pay-for-performance programs. This, in essence, encapsulates the benefits that supporters of this new system believe will be realized, even though many of these experts may not be involved in actual day-to-day medical practices. Detractors of the system see the same granularity as burdensome. The estimated cost per physician is projected to range from $25,000 to $50,000. Further, they argue that the ICD-10 classification is extremely complicated, and expensive. Concerns exist that it is being implemented without establishing either the necessity or thinking through the unintended consequences. Opponents also argue that beyond financial expense, it is also costly in terms of human toll, hardware and software expenses and has the potential to delay reimbursement. There is also concern that an unintended consequence of granularity would be the potential for enhanced and unnecessary fraud and abuse investigations. The authors of this article favor postponing the implementation of the ICD-10 until such time as its necessity is proven and implications are understood.