Modification of RNA splicing represents a promising therapeutic strategy for treating genetic diseases. Several splice-switching drugs have already been approved, notably for spinal muscular atrophy and specific genotypes of Duchenne muscular dystrophy. While peripheral blood mononuclear cells and fibroblasts are commonly used to evaluate the efficacy of these drug candidates in patient-derived samples, such approaches may lead to misleading conclusions due to the cell type-specific nature of RNA splicing. Induced pluripotent stem cells (iPSCs), which can be differentiated into various somatic cell types, offer a valuable tool to overcome this limitation. Once efficient differentiation protocols are established, iPSCs can give rise to neurons, retinal cells, cardiomyocytes, and other hard-to-obtain cell types. In this chapter, we describe a protocol for evaluating the splice-modification efficacy of drug candidates in iPSC-derived neurons, using the removal of a poison exon in SCN1A gene, associated with Dravet syndrome as a model.