The etiology of strabismus has long been observed to have a genetic component. Recent advances in genetic methodology may provide insight into the genetic basis for several types of inherited strabismus, including those associated with genetic multisystem disorders such as Moebius syndrome, Prader-Willi syndrome, craniofacial dysostoses, and mitochondrial myopathies. Inheritance of primary forms of strabismus, such as congenital ocular fibrosis, Brown syndrome and Duane syndrome, has been reported, but less is known of the defective genetic sites. The genetic basis for isolated strabismus that clusters in families, such as infantile esotropia syndrome, is also not yet known, but new techniques of molecular biology may now permit linkage detection in these families. By identifying affected families, clinicians will take part in unraveling the genetic basis of hereditary strabismus syndromes.