Splenic marginal zone lymphoma (SMZL) is a well-recognized entity in which chromosomal aberrations seem to be potential markers in diagnosis, prognosis and disease monitoring. FOXP1 is a transcriptional regulator of B lymphopoiesis that is deregulated in some types of NHL. Translocation t(3;14)(p14;q32) has been described in marginal zone lymphomas but few series have studied FOXP1 involvement in SMZL. We performed cytogenetic, fluorescence in situ hybridization (FISH) and immunohistochemical (IHC) studies in a series of 36 patients in order to study the status of FOXP1 in this entity. According to our results, FOXP1 is not rearranged in SMZL, although we were able to demonstrate gains of FOXP1 gene due to trisomy 3/3p by FISH. FOXP1 protein expression seemed to be not related to any aberration and IHC studies are not conclusive.