OBJECTIVE: To examine the feasibility and practicability of quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) with SYBR GREEN I fluorescence for detecting the MYCN mRNA expression in neuroblastoma cell line LA-N-5. METHODS: MYCN mRNA expression in LA-N-5 cells was measured using real time RT-PCR with SYBR GREEN I. Glyceraldehyde phosphate dehydrogenase (GAPDH) was used as internal control. The level of the MYCN mRNA was calculated as MYCN copies/GAPDH copies. RESULTS: Standard curves were linear and showed high correlations (R2>0.99). The ratio of MYCN mRNA copies to GAPDH mRNA copies was calculated based on specific PCR products. The MYCN mRNA level in LA-N-5 cells was obtained (17.4±1.2). CONCLUSIONS: Quantitative RT-PCR with SYBR GREEN I fluorescence may be a sensitive and reliable method for detecting the MYCN mRNA expression. It may also be potential applicable for detecting the MYCN mRNA expression in the small amount neuroblastoma tissues.［Chin J Contemp Pediatr, 2007, 9 (1):47-50］