[Background]: The presence of genetic changes is a hallmark of chronic lymphocytic leukemia (CLL). The most common cytogenetic abnormalities with independent prognostic significance in CLL are 13q14, ATM and TP53 deletions and trisomy 12. However, CLL displays a great genetic and biological heterogeneity. The aim of this study was to analyze the genomic imbalances in CLL cytogenetic subsets from both genomic and gene expression perspectives to identify new recurrent alterations. [Patients and methods]: The genomic imbalances and expression levels of 67 patients were analyzed. The novel recurrent abnormalities detected with bacterial artificial chromosome array were confirmed by FISH and oligonucleotide microarrays. In all cases, gene expression profiling was assessed. [Results]: Copy number alterations were identified in 75% of cases. Overall, the results confirmed FISH studies for the regions frequently involved in CLL and also defined a new recurrent gain on chromosome 20q13.12, in 19% (13/67) of the CLL patients. Oligonucleotide expression correlated with the regions of loss or gain of genomic material, suggesting that the changes in gene expression are related to alterations in copy number. [Conclusion]: Our study demonstrates the presence of a recurrent gain in 20q13.12 associated with overexpression of the genes located in this region, in CLL cytogenetic subgroups. ; This work was partially supported by grants from the Spanish Fondo de Investigaciones Sanitarias (02/1041 and FIS 09/01543); Fondo Social Caja de Burgos de Investigación Clínica, Proyectos de investigación del SACYL (106/A/06) and by the ‘Acción Transversal del Cáncer’ project, through an agreement between the Instituto de Salud Carlos III (ISCIII), Spanish Ministry of Science and Innovation and the Cancer Research Foundation of Salamanca University and the Redes de Investigación RTIIC (FIS). AER is fully supported by an ‘Ayuda predoctoral FIS de formación en investigación’ by the Spanish Fondo de Investigaciones Sanitarias. ; Peer Reviewed