A convenience sample of 164 adult patients with 185 glass-caused wounds who presented to an emergency department (ED) and consented to a radiograph was prospectively studied. The purpose was to determine the characteristics of wounds at high risk for foreign body (FB) and the predictive value of patient FB sensation and probing wound exploration for FB retention. Retained glass was located in 28 (15%) wounds. Motor vehicle as a mechanism of injury (P=.003), head as a location (P=.035), and puncture as wound type (P=.002) were more likely to be associated with retained FBs (chi2 analysis). Patients with wounds with glass were more likely to have a positive perception of a foreign body (41%) than those with no glass (17%) (P=.005). The positive predictive value of patient perception was 31%; negative predictive value was 89%. In five cases, wound exploration was negative and subsequent radiograph was positive for FB. In one of these cases, a 4-mm glass FB was removed; in the other four, no FB was found. In conclusion, head wounds resulting from motor vehicle accidents or puncture wounds are more likely to harbor retained glass FBs. Patients with glass FB in wounds are more likely to have a positive perception of FB; however, a positive perception has a low predictive value of glass FB. In this series, a negative wound exploration made the presence of retained FB greater than 2 mm less likely but did not rule out the presence of retained glass.