Lactate dehydrogenase B (LDHB) expression and the level of serum LDH were involved in tumor progression. Correlations between these parameters and their prognostic significance were not assessed in non-small cell lung cancer (NSCLC). We evaluated LDHB expression by immunohistochemical method and serum LDH in 243 NSCLC patients treated with surgical resection [136 adenocarcinomas (ADCs), 89 squamous cell carcinomas (SqCCs) and 18 other type carcinomas]. Correlation between LDHB expression and serum LDH was assessed, and the prognostic significance was determined. LDHB expression was identified in 52% of SqCC and 55% of ADC tissue samples. LDHB-positive SqCC patients had a higher recurrence-free survival (RFS) rate than LDHB-negative patients (p=0.017). LDHB-positive and LDHB-negative patients showed similar RFS rates in ADCs (p=0.519). Multivariate analysis showed that LDHB expression was an independent risk factor in lung SqCCs (hazard ratio=0.393, p=0.028). A positive correlation was found between LDHB expression and serum LDH level (p=0.02). High LDHB expression is significantly associated with the level of serum LDH and better clinical outcomes in lung SqCC.