During the 3 years of the study, 98 patients (83 male and 15 female) with blunt trauma were selected for NOM for renal, hepatic and splenic injuries. Mean age was 26.1 ± 17.7 years (range, 2–89) and the mean injury severity score (ISS) was 14.5 ± 7.4. The success rate of NOM was 93.8%. Fifty-one patients (43 men, eight women; mean ISS, 14.2 ± 5.8) underwent NOM of splenic trauma, 38 patients (33 men, five women; mean ISS, 12.9 ± 8.2) hepatic trauma, and nine patients (seven men, two women; mean ISS, 22.2 ± 7.6) renal trauma. Six patients underwent laparotomy due to the failure of NOM. The success rates of this treatment were 94.1%, 94.7% and 88.8% for the spleen, liver and kidney injuries, respectively. Female gender and ISS were significant predictors of the failure of NOM (P = 0.005 and P = 0.039, respectively).