The outcome of chronic myeloid leukemia has been greatly improved by the use of Imatinib (IM), a selective BCR/ABL kinase inhibitor. The aim of present study was to report long term follow-up & outcome of IM-treated CML patients along with their clinicopathological features, risk group stratification, adverse events and to compare it with CML patients reported from western countries. The mean follow-up of 123 CML patients was 5.5 years in present study, who were treated with frontline IM 400mg daily in a tertiary care hospital in Pakistan. Risk stratification scores, response to treatment (ELN guidelines) and survival outcomes estimated by Kaplan-Meier analysis. Mean age: 35 years (9-67 years) and M: F: 1.5:1, mean follow up time: 5.5 years (1-15 years). Overall survival (OS): at 5.5, 8, 10 and 12 years were 93%, 88%, 81% and 73%, respectively. Progressions free survival (PFS) was 95%, 83%, 83% and 78% at 5.5, 8, 10 and 12 years, respectively. OS estimate by Sokal score was significant (P-value: 0.0019). Additional chromosomal aberrations: 1.6%. Eighteen (14.6%) patients progressed to AP/BC. Adverse events were moderate and tolerable. We present findings from a long term follow up of CML patients treated with IM in a developing country. CML mean age at onset was considerably lower than the western populations. Furthermore, 5.5 years OS are comparable to western CML population. IM in our patients as frontline choice proved to be very effective. IM was found to be well tolerated, safe with manageable moderate side effects.