Dysferlin gene mutations causing LGMD2B are associated with defects in muscle membrane repair. Four stable cell lines have been established from primary human dysferlin-deficient myoblasts harbouring different mutations in the dysferlin gene. We have compared immortalized human myoblasts and myotubes carrying disease-causing mutations in dysferlin to their wild-type counterparts. Fusion of myoblasts into myotubes and expression of muscle-specific differentiation markers were investigated with special emphasis on dysferlin protein expression, subcellular localization and function in membrane repair. We found that the immortalized myoblasts and myotubes were virtually indistinguishable from their parental cell line for all of the criteria we investigated. They therefore will provide a very useful tool to further investigate dysferlin function and pathophysiology as well as to test therapeutic strategies at the cellular level.