Using ultrasound for detecting soft tissue foreign bodies seems to be the preferred choice with minimum invasion and easy availability at the bedside in emergency departments. In this study, a workshop (1 hour of lecture presentation and 3 hours of interactive hands-on) was designed to evaluate the efficacy of a short course of simple interactive training to improve the ability of emergency medicine residents to detect foreign bodies with ultrasound. Eight pieces of fresh full thickness (10 x 10 x 10 cm) lamb leg muscle were used in this study. Five different types of foreign bodies, including: a piece of glass (5 x 5 x 4 mm), wood (5 x 5 x 4 mm), gravel (5 mm diameter), plastic (5 x 5 x 2 mm) and a nail (25 mm in length) were placed deep inside each lamb leg. An ultrasound machine with a 7.5 MHz linear probe was used in this study. 35 emergency medicine residents (12 PGY1, 11 PGY2 and 12 PGY3) were enrolled in this study. Pretest and post-test results were compared and analyzed. Among all 35 participants in the training session, foreign body detection was significantly improved after the workshop (p < 0.001). Overall sensitivity and specificity for differentiating the presence and absence of a foreign body with 95% confidence were 60% (75% for PGY3) and 85.7% (91.7% for PGY3), respectively. The overall accuracy increased from 20.2% to 72.8% due to this session. This study supported the possibility of using ultrasound to detect foreign bodies by emergency physicians with a very short training course. This is highly beneficial for overcrowded emergency departments.