Neutropenia is a major risk factor for bacterial colonization and sepsis in preterm neonates in the neonatal intensive care unit (NICU), but little is known about its relationships with candidal colonization (CC) in these settings. We performed a case-control study on neonates with birth weight of <1500 g admitted to our NICU during a 7-year period (1996-2003, N = 585). Through database search, infants with early-onset neutropenia (EON) (n = 68, group A) were identified and 1:1 matched with controls without EON (n = 68, group B). Microbiologic data from weekly surveillance cultures were examined to determine the presence and intensity of CC. Groups A and B were similar clinically and demographically. All group A neonates recovered from EON before the 8th day of life. Incidence of CC in the 1st month of life (at least 1 site) was significantly higher in group A (61.8% versus 35.3%, P = 0.002) and was not modified by treatment with recombinant granulocyte colony-stimulating factor. The same was true of CC intensity, expressed as the number of sites affected (P = 0.002). Incidence of candidal sepsis, mortality rates, and relative frequencies of the various subspecies of Candida among the isolates did not significantly differ between the 2 groups. In conclusion, EON in preterm neonates is a significant, independent risk factor for CC. Larger, prospective, adequately powered studies should verify whether increased CC related to neutropenia may translate into a similar increased occurrence of candidal sepsis in these settings.