Study objective: To determine the types of injuries sustained during the use of in-line skates and to compare them with injuries sustained during the use of roller skates and skateboards, which have similar riding mechanics; and to assess the protection afforded by wrist, elbow, and knee guards. Methods: The study population was a consecutive series of injured patients who presented to the emergency department of a Level I trauma center between May 1992 and October 1993. Results: Of the 137 patients with skating injuries evaluated in the ED during the study period, 63 (46%) were in-line skaters,36 (26%) were roller skaters, and 38 (28%) were skateboarders. Minor injuries (sprains, bruises, lacerations) were more common than fractures, and there was no statistical difference in the types of injury between skater groups (P=NS). The most common serious injury was fracture of the distal arm, which occurred in each of the three skater groups (43%, n=59). Of these patients, 37% (n=21) required open or closed orthopedic reduction. More fractures of the distal forearm or elbow occurred among skaters who had not been wearing wrist guards (P=.013; risk ratio, 2.07; 95% confidence interval, 1.37 to 3.13). Only 25% of skaters used any protective equipment. In-line skaters owned and used protective equipment more often than did roller-skaters or skateboarders. Most injuries occurred while the patient was traveling in the street or on the sidewalk. Injuries occurred more commonly because the skater was going too fast (35%), because the skater struck an object in the pavement (20%), or because the skater was unable to brake (19%) than because of equipment failure (2%) or interference from motor vehicles (3%). Conclusion: Injuries sustained by in-line skaters were similar to those sustained by roller skaters and skateboarders. The risk of wrist or elbow fracture is greater when wrist guards are not worn. [Orenstein JB: Injuries and small-wheel skates. Ann Emerg Med February 1996;27:204-209.]