It has been suggested that some cases of nonimmune chronic idiopathic neutropenia of adults (NI-CINA) may be considered preleukemic disorders. This paper describes two patients with NI-CINA who developed acute myeloid leukemia (AML) 34 and 64 months, respectively, following NI-CINA diagnosis. Patient 1 presented erythema nodosum and patient 2 polyarthritis of the large joints 9 and 2 months, respectively, before AML. Patient 1 had AML M4 disease associated with aberrant expression of CD7 and CD19 cell surface markers and one abnormal clone in bone marrow karyotype. Patient 2 had myeloid/natural killer (NK) cell leukemia with expression of CD7 and CD56 molecules and four derivative abnormal clones in the karyotype. Both patients had del(5)(q22q35) in common. No mutations in the transmembrane or the intracytoplasmic domain of the granulocyte colony-stimulating factor (G-CSF) receptor were found. The first patient had disease resistant to chemotherapy from the beginning of the treatment and the second following a brief complete hematological remission. On the basis of these observations, we concluded that a causal link of AML with the underlying NI-CINA cannot be presently justified, but the unusual findings noted in our patients prompt the description of additional cases for a further investigation of the relationships, if any, between these two granulocytic disorders.