During culture adaptation, human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) tend to acquire chromosomal aberrations. Generally, stem cell lines are screened for large-scale chromosomal changes using low resolution karyotype analysis. Recent studies characterizing human stem cells using array-comparative genomic hybridization (aCGH) suggests most abnormalities acquired during culture are under the resolution of karyotype analysis and therefore are routinely missed. Here, we describe a custom-designed stem cell focused microarray utilizing 44K probes, with increased resolution in relevant stem cell-associated and cancer-related genes.