Peripheral neuroblastic tumors (PNT), are heterogeneous neoplasms that include neuroblastoma (NB), ganglioneuroblastoma (GNB) and ganglioneuroma (GN) and present great biological heterogeneity. There are few reports analyzing PCNA and Ki-67 expression in PNT; however, controversy exists concerning the specificity of PCNA as a real proliferative marker. The objective of our study was to determine which of these cellular proliferation markers is more specific on cellular cycle and could contribute with more information on the cell cycle. We found that PCNA was expressed in NB unfavourable cases, with MYCN amplification and high mitosis-karyorrhexis-index (MKI). Whereas, Ki-67 showed statistical significance regarding cases unfavourable with intermediate and high MKI, aneuploid and stages 3 and 4. Survival showed that patients with tumor not expressing Ki-67 (MIB1) lived longer than those without PCNA (88.93 vs 74.05%). We conclude that Ki-67 expression permits reliable detection of the cellular proliferation neuroblastoma fraction and provides useful prognostic information when associated with other biological factors.