Forty-one children were identified with autoimmune neutropenia of infancy and early childhood (absolute neutrophil count [ANC] less than 500/μ and demonstrable serum antineutrophil antibodies). There were 21 boys and 20 girls; the median age at diagnosis was 11 months (range 5-38 months). No life-threatening infections occurred. There was a gradual upward trend in ANC in all patients over many months, with 87% having an ANC >1000/μl by 24 months from diagnosis. Among various clinical and laboratory parameters analyzed statistically, only younger age at diagnosis was associated with earlier neutrophil recovery. There was no association between degree or duration of neutropenia and sex, race, antibody reactivity, or presence of serious illness at diagnosis.