Drug dosages used during pediatric emergencies and resuscitation are often based on estimated body weight. The Broselow Tape, a tape measure that estimates weight and drug dosages for pediatric patients from their length, has been developed to facilitate proper dosing during emergencies. In our study, 937 children of known weight were measured with this tape. Weight estimates generated by the tape were found to be within 15% error for 79% of the children. The tape was found to be extremely accurate for children from 3.5 to 10 kg, and from 10 to 25 kg. Regression lines of estimated compared with actual weight for these children have slopes of 0.98 and 0.96, respectively, not significantly different from the ideal slope of 1.00 (P = 28 and .13). Accuracy was significantly decreased for measured children who weighed more than 25 kg. In a separate group of children (n = 53), the tape was shown to be more accurate than weight estimates made by residents and pediatric nurses (P less than .0001). Use of the Broselow Tape is a simple, accurate method of estimating pediatric weights and drug doses and eliminates the need for memorization and calculation.