The presence of genetic alterations was investigated by SNP array in combination with conventional and spectral karyotyping and fluorescence in situ hybridization analysis of 75 consecutive pediatric bone marrow samples. The samples were collected at diagnosis from all children diagnosed with malignant hematological disease between 2006 and 2010 at a single diagnostic center in Gothenburg, Sweden. Conventional cytogenetic and molecular genetics techniques are up to this date essential for the clinical laboratories but there is a need for higher resolution techniques in order to identify new genetic markers that eventually can improve the management of these disorders. Here, we conclude that the addition of SNP array-based karyotyping combined with conventional cytogenetics increase the diagnostic accuracy of pediatric hematological malignancies. The two techniques enhance the cytogenetic image and should not be contrasted as they meet distinct important roles. Since balanced translocations cannot be detected with the SNP arrays of today and tumor-specific translocations are very important diagnostic and prognostic indicators we suggest that SNP-based array is a valuable adjuvant tool in the cytogenetic diagnostics of pediatric leukemias but cannot replace currently used techniques, i.e. G-banding, SKY and FISH analysis.