To determine the relationship between pubertal development and postpubertal gonadal function in childhood cancer survivors. Childhood cancer survivors (≥10 years of age) who received follow-up care in a pediatric oncology group in an academic medical center during the period from January 1, 1985, to July 1, 2010 were included in this case series. Their pubertal development and gonadal function were evaluated. The cohort consists of 39 males (age 10-21 years) and 35 females (age 10-29 years) with a variety of cancer diagnosis and treatments. The average age at diagnosis was ∼7.5 years. The average age at the time of the study was 16 and 16.7 years in males and females, respectively, representing a mean follow-up interval of ∼9 years. Despite the fact that 60% of survivors received cyclophosphamide equivalents and 16.2% received cranial radiation or brain tumor resection, the majority of survivors (68%) presented with both normal puberty and normal gonadal functions at the time of follow-up. In 27% of survivors, puberty development did not predict gonadal function in early adulthood: 20% of survivors had normal puberty, but abnormal gonadal function; 7% of survivors had abnormal puberty, but gonadal function remained normal as young adults. Most childhood cancer survivors had normal puberty and gonadal function despite a variety of cancer treatment modalities. However, normal puberty did not predict normal gonadal function later in life in many survivors. Therefore, close follow-up with gonadal function in adolescent and early adulthood years is essential.