Acute lymphoblastic leukemia is the most common malignancy in children with a 5-year survival rate, accounting for 80% of cases. Melanoma is rare in children and has been reported as a sporadically occurring secondary malignant neoplasm in children with acute lymphoblastic leukemia. This study presented a 10-year-old Iranian child with pre-B-cell acute lymphoblastic leukemia that was diagnosed at age 6. She was fully recovered after 2 years of treatment. One year and six months after cessation of treatment, she was referred with a 1×2 cm mass in her right parietal region of scalp. Biopsy of the lesion confirmed the diagnosis of malignant melanoma. Computed tomography scan of the chest and abdomen also confirmed extensive liver metastasis which was corroborated by liver biopsy. Bone scan also revealed bone metastases. Early diagnosis and treatment of these tumors is extremely important and these patients should be closely monitored and undergo regular physical examination.