BACKGROUND The objective of this study was to identify the risk factors for new-onset diabetes mellitus (NODM) after kidney transplant in pediatric renal transplant recipients using Organ Procurement Transplant Network/United Network of Organ Sharing database. METHODS A total of 2726 nondiabetic primary kidney transplant recipients (age 2-20 years, transplanted between July 2004 and December 2007) in the Organ Procurement Transplant Network/United Network of Organ Sharing database as of August 2008 with at least one follow-up report were included. We examined the risk factors for NODM using multivariate Cox regression analysis using the time to NODM reported as a time-varying endpoint. In recipients with functional graft at 1 year after transplant, the graft survivals during subsequent 24 months were compared according to the presence of NODM within first year of transplant. RESULTS NODM was reported in 4.6% (median follow-up time: 693 days). Independent risk factors for NODM included increased age (>10 years vs. <10 years, hazard ratio [HR]=2.143, P=0.015), abnormal body mass index percentile (<5% or >85% vs. 5%-85%, HR=1.697, P=0.01), and steroid use at discharge (yes vs. no, HR=3.573, P=0.03). Living donor transplant was associated with a decreased risk of NODM (living vs. deceased, HR=0.629, P=0.05). NODM within first year of transplant was not associated with inferior graft survival during subsequent 24 months. CONCLUSIONS Some of the identified risk factors for NODM are potentially modifiable, including abnormal body mass index percentile and the use of steroid. Prospective clinical trials are needed to assess whether modifying these risk factors will prevent NODM.