Background.: This study examined trends in the numbers of double contrast barium enemas, flexible sigmoidoscopies, and colonoscopies and trends in the choices of colorectal cancer screening service providers. Methods.: Descriptive statistics were used to examine Medicare and Tricare data for the years 1999 to 2001. Results.: The total volume of procedures increased 5% and 14%, respectively, in Tricare and Medicare. Tricare and Medicare, respectively, saw 32% and 33% reductions in barium enemas and 28% and 41% reductions in flexible sigmoidoscopies. Colonoscopies increased by 45% and 34% in Tricare and Medicare, respectively. Gastroenterologists provided the majority of colonoscopies for both groups each year. Conclusions.: The volume of colonoscopies increased from 1999 to 2001 for both groups while the volumes of barium enemas and flexible sigmoidoscopies decreased. Gastroenterologists appear to be the preferred providers of colonoscopies. © 2006 Elsevier Inc. All rights reserved.