RESUMEN Metodos: Mediante analisis por RT-PCR del RNAm extraido de leucocitos de sangre periferica obtenida de pacientes Resultados: De doce pacientes evaluados, el 67% (ocho) presentaron el transcrito b2a2 y 33% (cuatro) presentaron el transcrito b3a2. Conclusion: Esta proporcion mayor para b2a2 difiere de lo observado en otros estudios mundiales: Inglaterra, Japon, Italia, Espana pero se aproxima a los hallazgos de estudios mexicanos y ecuatorianos. Palabras clave: Leucemia, transcritos de fusion, transcritos b2a2 y b3a2, reaccion en cadena de la polimerasa (PCR), fusion BCR/ABL HIGH PROPORTION OF BCR/ABL IN PATIENTS WITH CHRONIC MYELOID LEUKEMIA IN COLOMBIA ABSTRACT Methods: By RT-PCR analysis of mRNA extracted from peripheral blood leukocytes obtained from patients evaluated, 67% (eight) presented the b2a2 and 33% (four) presented the b3a2 transcript. Conclusion: This larger proportion of b2a2 differs from that observed in other global studies: England, Japan, Italy, Spain but is close to the findings of Mexican and Ecuadorian studies. Key words: Leukemia, fusion transcripts, b2a2 and b3a2 transcripts, polymerase chain reaction (PCR), BCR/ABL fusion