Mixed-lineage leukemia (MLL) gene rearrangements have rarely been reported in pediatric lymphoma despite their high prevalence in pediatric leukemia. We present a case of an infant with bilateral ovarian B-lineage lymphoblastic lymphoma with MLL gene rearrangement. We also briefly summarize the clinicopathologic significance of MLL gene rearrangements, and review the reported cases of pediatric ovarian lymphoma with and without MLL rearrangement.