The purpose of this research is to evaluate the quality of colonoscopy at an academic institution with a focus on factors influencing withdrawal times and adenoma detection rates. Procedural data and pathologic results of 550 consecutive screening colonoscopies in average risks patients (mean [+/- SD] age, 57 +/- 7.6, 44% male) completed by ten academic gastroenterologists were reviewed. Per individual gastroenterologist, the adenoma detection rates ranged widely from 0.09 to 0.82 adenomas per patient with a mean of 0.46 for the group. The mean withdrawal time was 7.0 min for the group and ranged from 3.4 to 9.6 min. There was a significant positive relationship between the number of adenomas detected and the withdrawal time (P = 0.006). Endoscopists with cecal intubation time to withdrawal time ratios of less than 1 detected significantly more adenomas compared to endoscopists with ratios greater than 1 (P = 0.001). ( 1) Significant variation in academic gastroenterologists' abilities to detect adenomas during screening colonoscopies exists. ( 2) Colonoscopic withdrawal time and the cecal intubation to withdrawal time ratio are important factors associated with increased adenoma detection rates.