A Chinese girl presented with generalized papular rash and monocytic leukemia 19 days after birth. Cytogenetic analysis showed t(8;16)(p11.2;p13.3) as the sole chromosomal abnormality. Spontaneous regression of the leukemia was observed after 2 months, although the t(8;16) translocation persisted cytogenetically. This was followed 7 months later by the development of acute myeloid leukemia with maturation and cytogenetic evolution with extra chromosomes 4 and 8. Molecular study showed that the reciprocal MYST3 and CREBBP gene fusion characteristic of t(8;16) translocation persisted throughout the clinical course, even during spontaneous regression of the neonatal leukemia, and after chemotherapy-induced remission of the subsequent acute myeloid leukemia. The genetic lesion only became undetectable at the molecular level at the age of 20 months. The possible role of MYST3 and CREBBP gene fusion in the pathogenesis of the leukemia is discussed.