A randomized, controlled, parallel-group study was perform to compare the clinical efficacy of a semi-rigid bandage ('Scotchrap') with the standard adhesive tape treatment for ankle ligament injuries. The semi-rigid bandage support wrap consists of a knitted fibreglass fabric impregnated with a polyurethane resin. The cotton stockinet and the synthetic cast padding are used for protection of pressure points and any bony prominences. Prior to application, the 'Scotchrap' must be soaked in water after which it is applied in a way similar to that used for a plaster of paris bandage. The finished bandage remains elastic, allowing normal dorsal and plantar flexion of the foot, but preventing inversion and eversion, and pronation and supination. A t rest, the bandage always redresses the immobilized ankle into the neutral position, One hundred and thirty-six patients were included in the study. The semi-rigid bandage group comprised 59 patients and the tape group had 57 patients. These two groups were statistically comparable. The intake questionnaire included a general and a specific anamnesis form as well as a physical examination form. Follow-up data were recorded every 2 weeks. After termination of the treatment, the patients evaluated treatment efficacy. Statistical analysis of 126 items per patient with chi2-tests (p less-than-or-equal-to 0.05) and Fisher's exact tests (p less-than-or-equal-to 0.05) revealed no statistical significant differences in treatment result. The patient assessments of treatment efficacy of both types of bandage were also comparable. Both types of bandage gave sufficient stability (98%; p<0.005) and were equally effective. This study has shown that 'Scotchrap' can be used for lateral ankle ligament lesions with excellent short-term results. The technique for application of the 'Scotchrap' bandage is easy to learn, but must be considered thoroughly because any change in the technique will lead to changes in the rigidity of the bandage and early wastage. The semi-rigid bandage can also be used for the functional treatment of patients who are allergic to tape. Of more interest are the other fields of application in which this new material can be used, e.g. orthopaedic corsets, after-treatment for knee arthroscopies, achilles tendon ruptures, or even for wrist fractures. It is concluded that, alone or in combination with other cast-immobilization techniques, the semi-rigid 'Scotchrap' bandage represents a welcome and useful contribution to the existing assortment of bandage materials.