Background: Readmission temporally close to discharge can best reflect the quality of care received in the last hospitalization, and has been considered a valuable indicator for the quality of care received. The aim of the present study was to investigate the incidence of and predictors for readmission within 31 days after discharge among preterm low-birthweight (PLBW) infants (ICD-9-code: 765.0x) in Taiwan. Methods: Based on Taiwan's National Health Insurance claim data, a population-based cohort including a total of 18 421 PLBW infants born and hospitalized in 2000-02, was analyzed. The cumulative incidence rate (CIR) of readmission and the hazard ratio of readmission in relation to potential predictors were calculated. Results: The total number of participants readmitted within 15 or 31 days after discharge was 1763 and 2484, representing a CIR of 9.6% and 13.5%, respectively. Significant predictors for readmission within 15 or 31 days were essentially similar. Male gender, weight <1000 g, presence of congenital abnormalities, and lung disease were significant risk factors for readmission. Shorter length of hospital stay (<35 days) was associated with a reduced risk of readmission, and there were significant geographic and hospital variations of readmission, with higher rates noted in the most urbanized area and at regional hospitals. Conclusion: The short-term readmission rate among Taiwanese PLBW infants is higher than in Western countries. Future studies should be conducted to investigate the causes of apparent geographic and hospital variations of readmission rates in order to make more specific interpretations.