Our objective was to determine the impact of abdominal ultrasound (US) on 1) the use of diagnostic peritoneal lavage (DPL) and abdominal computed tomography (ACT) for diagnosing blunt abdominal trauma (BAT) and on 2) surgical resident training. The study design was a retrospective chart review. Patients sustaining BAT who had ACT or DPL done during the 1-year period before the introduction of US (pre-US) were compared with those from a 1-year period beginning 6 months after US (post-US). Data collected included diagnostic modality, demographic data, mortality, associated injuries, length of stay, mechanism of injury, and number of exploratory laparotomies. Of 128 patients in the pre-US group, 35 patients (27%; P < 0.001) underwent DPL, 0 patients (0%; P < 0.001) received US, and 92 patients (72%) received ACT, with positive results for 31 patients (34%). Exploratory laparotomy was performed on 35 patients (27%) in the pre-US group. Of 140 patients in the post-US group, 8 patients (6%; P < 0.001) underwent DPL, 120 patients (85%; P < 0.001) received US, and 108 patients (77%) received ACT, with positive results for 44 patients (42%). Exploratory laparotomy was performed on 22 patients (15%; P < 0.001) in the post-US group. Resident experience with DPL before and after the introduction of US and availability of US for graduated residents was documented. Chi-square and Fisher's exact test were used for statistical analysis. Resident experience changed from 22 to 3 DPLs per year in the pre- and post-US groups, respectively. Ten per cent of graduating residents had US available for use after leaving this institution. US replaced DPL and resulted in slightly more positive ACT scans in assessing BAT at our institution. Paradoxically, only 10 per cent of graduating residents had US available after leaving this institution. Until the use of US for diagnosing BAT has widespread use in the community, we must question our adequacy of resident preparation for diagnosing BAT.