Background:The most frequent cytogenetic aberration is 13q14.3 deletion in Chronic Lymphocytic Leukemia (CLL). Hsa-miR-15a/hsa-miR-16-1 are tumor suppressor miRNAs encoded from 13q14.3 region. Objectives: The aim of this study was to investigate the 13q14.3 deletion using molecular and cytogenetic techniques and association with miRNA-15a/miRNA-16-1. Materials & Methods: We used peripheral blood samples of 30 CLL patients which were either induced and or non-induced with DSP30+IL-2 for determine 13q14.3 deletion by karyotyping and iFISH methods. Expression levels of hsa-miR-15a/miR-16-1 were measured using Quantitative Real Time PCR and compared with deletions. Results: 13q14.3 deletion was detected in 8.6% of cases by karyotyping and in 65% by iFISH. Mosaic forms (monoallelic+biallelic) were observed in 50% of cases. Besides determining common chromosome abnormalities such as add(2)(q37), t(2;7)(p11.2;q22), del(6)(q13q21), del(6)(q25), add(9)(q21), del(11) (q23), t(11;14)(q13;q32), del(13)(q11q12), del(13)(q12q14), add(14)(q23), del(14)(q23), t(14;19)(q32;q13.1), del(15)(q23), del(17)(p12), t(18;22)(q21;q11.2), add(21)(p13) and t(17;21)(q11.2;122), we also determined t(1;13)(q32;q34), inv(2)(p25q21), del(13) (q22q32), t(14;19)(q24;q13), dup(17)(q21q23), rob(21;21)(p13;p13) which have not been reported previously. Mitotic index data was found statistically significant and DSP30+IL-2 increased mitotic index by 2.5 folds. Association between decreased miR- 16-1 expression and deletions was statistically significant. Conclusion: We suggest that cytogenetic and iFISH analyses are complementary and use of DSP30+IL-2 is effective in CLL. Decreased expression of hsa-miR-16-1 is remarkable.