We investigated the treatment results and probable prognostic factors in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) treated with neoadjuvant chemotherapy (NCT) plus conventional radiotherapy (RT) or concomitant chemoradiotherapy (CCRT) at our hospital. We retrospectively evaluated 61 patients (48 males, 13 females) with locoregionally advanced NPC treated either with 2 cycles of NCT plus RT (Group A, 37 patients) or with three cycles of NCT plus CCRT (Group B, 24 patients) between September 1995 and October 2002. According to the AJCC 1997 classification system, 19 patients had Stage III disease and 42 had Stage IV. NCT consisted of cisplatin and 5-fluorouracil. Total RT doses were ranged between 59.4-71.6 Gy (median: 66.2 Gy). Concomitant cisplatin (75 mg/ m(2)) was given on first days of Weeks 1, 4, 7 of CCRT. Patient sex, histopathologic subtype, T status, ECOG performance status, stage, serum lactate dehydrogenase (LDH) level, and cranial nerve involvement at diagnosis were comparable in the 2 groups. There were statistically significant differences between median follow-up times and N status for the 2 groups. Fifty-five (90.2 percent) patients completed all planned NCT. Univariate analysis revealed the pretreatment LDH level as the only statistically significant prognostic factor for disease-free survival (DFS) and overall survival (OS). Four-year DFS rates were 55.9 percent and 21.3 percent for patients with normal and high serum LDH levels, respectively (P = 0.04). Four-year OS rates were 68.7 percent and 28.5 percent for patients with normal and high serum LDH levels, respectively (P = 0.01). Multivariate analysis also revealed that high serum LDH level was the only independent risk factor that predicted OS. The relative risk was 2.43 (95% CI: 1.08-5.45) for patients with high serum LDH levels (P = 0.03). No independent risk factors associated with DFS were found for other prognosticators. Our study demonstrated that high serum LDH level is the only independent unfavorable risk factor for OS in patients with locoregionally advanced NPC who were treated with NCT plus RT or CCRT.