We present the study of 16 cases of splenic marginal zone B-cell lymphoma (SMZBL) combining conventional cytogenetics and fluorescence in situ hybridization technique (FISH). We used a locus specific probe (11q22.3) that hybridizes with Ataxia Telangiectasia Mutated gene (ATM) and a centromeric probe of chromosome 11 as a control. Deletions in ATM gene region have been found in B-cell chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL) and have been considered as an independent prognosis factor in these pathologies. The aim of our study was to determine the ATM status in SMZBL because no specific studies concerning ATM status in SMZBL have been reported and other B-cell malignances have shown ATM deletions. No deletions were detected in any of the 16 cases. ATM deletions could be considered a rare event in SMZBCL.