To ascertain whether dystrophin immunohistochemistry could improve DMD/BMD carrier detection, we analyzed 14 muscle biopsies from 13 DMD and one BMD probable and possible carriers. All women were also evaluated using conventional methods, including genetic analysis, clinical and neurological evaluation, serum CK levels, EMG, and muscle biopsy. In 6 cases, there was a mosaic of dystrophin-positive and dystrophin-deficient fibers that allowed to make the diagnosis of a carrier state. Comparing dystrophin immunohistochemistry to the traditional methods, it was noted that this method is less sensitive than serum CK measurements, but is more sensitive than EMG and muscle biopsy. The use of dystrophin immunohistochemistry in addition to CK, EMG and muscle biopsy. improved the accuracy of carrier detection. This method is also helpful to distinguish manifesting DMD carriers from patients with other neuromuscular diseases like limb-girdle muscular dystrophy and spinal muscular atrophy.