The American Association for the Surgery of Trauma developed an Organ Injury Scale for management of patients with splenic, kidney, or liver injuries. Despite widespread use of the guidelines, the person who determines the injury grade varies among institutions. Our purpose was to determine the accuracy and interobserver agreement between surgical residents and a radiologist in grading solid organ injuries. We retrospectively reviewed patients with solid organ injuries from January 2009 to May 2010 and compared the grade of solid organ injuries by a single resident with grades by a single blinded radiologist using a paired t test, analysis of variance, or Kruskal-Wallis. Computed tomography scans of 58 patients with splenic injuries, 43 with liver injuries, and 16 with kidney injuries were reviewed. Average grades for splenic injuries were 2.5 and 2.4 (radiologist/resident); liver injuries, 2.6 and 2.1; and kidney injuries, 2.7 and 2.8. There were no significant differences in grading by the radiologist and resident for splenic and kidney injuries; however, equal values were only achieved in 43 and 38 per cent, respectively. There was a significant difference (average rating difference 0.54, P = 0.0002) in grading between the radiologist and resident for liver injuries with only 35 per cent having equal values and the radiologist grading on average 0.5 points higher than the resident. No demographic, injury, or outcome variables were significantly associated with interobserver variability (P > 0.05). Despite a significant difference for liver injury grading, interobserver agreement between residents and a single radiologist was low. Clinical implications and the impact on outcomes related to interobserver variations require further study.