Griscelli syndrome is an autosomal recessive disorder characterized by pigmentary dilution and is occasionally associated with a hemophagocytic syndrome (type 2). We present a 13-year-old girl with Griscelli syndrome type 2, who developed a hemophagocytic syndrome along with marked muscle weakness and elevated plasma creatine kinase. Muscle biopsy showed massive inflammatory changes in some fascicles, while other fascicles were relatively spared. Clinical symptoms and biopsy changes resolved after immunosuppression and allogeneic hematopoietic cell transplantation. Our results suggest that muscle involvement should be considered in patients with hemophagocytic syndrome to ensure proper treatment.