The technology using induced pluripotent stem cells (iPSCs) has enabled us to differentiate into targeted cells and examine the specific phenotypes for patient-derived cells in culture dish. Spinal muscular atrophy (SMA) is an autosomal recessive disorders characterized by a loss of lower motor neurons, leading to infant mortality. SMA is caused by loss or mutation of the SMN1 gene and retention of SMN2, leading to reduced levels of ubiquitously expressed protein, survival motor neuron (SMN). The severity of symptom of SMA varies depending on the copy number of SMN2 and clinically classified into 3 groups (type 1-3) according to the onset and the severity of their presentation. Here we generated iPSCs from fibroblasts derived from type 1, 2 and 3 SMA patients. The generated iPSCs expressed human ES cell markers, carried normal karyotype and had a potential to differentiate 3 germ layers. We differentiated them into lower motor neurons using serum-free floating culture of embryoid body-like aggregates with quick reaggregation (SFEBq) method. We identified cell-specific phenotypes related to SMN protein decrement and explored the possible machinery of selective loss of motor neuron in SMA.