Retrospective review of imatinib monitoring through electronic health records (EHR) can provide valuable insight into the current management of chronic myelogenous leukemia (CML). This study retrospectively reviewed EHRs from 2001 to 2010 of patients with chronic phase CML (CP-CML) treated with first-line imatinib. Chart evaluations included a review of cytogenetic and molecular testing, overall survival, adverse drug events (ADEs), and therapy modifications. A total of 54 patients with CP-CML were treated with first-line imatinib and had either cytogenetic or molecular testing within 18 months of imatinib initiation. Within the first 18 months of treatment, 33 of 45 patients (73%) undergoing cytogenetic testing experienced a complete cytogenetic response (median, 241 days; range, 110-542 days) and 24 of 48 patients (50%) receiving molecular testing achieved at least a major molecular response (median, 253 days; range, 99-546 days). The average number of cytogenetic and molecular tests conducted within the first 18 months was 2.5 and 3.8, respectively. Nineteen of 54 (35%) had a dose increase of imatinib (>400 mg; median, 329 days; range, 21-1968 days). The 5-year estimated overall survival rate was 88.5%. Between 2006 and 2010 (n=30; 56%), 7 patients (23%) transitioned to dasatinib or nilotinib (median, 399 days from diagnosis; range, 180-1046 days) because of suboptimal response or treatment failure (n=5) and imatinib ADEs (n=2). Forty-six imatinib-associated ADEs occurred in 31 patients (57%), of which 10 (32%) received dose reductions (median, 52 days) and 6 (19%) had discontinuations (median, 139 days). Closely monitored patients with CML treated with imatinib at an NCCN Member Institution experienced outcomes comparable to those reported in key clinical trials.