The study was purposed to explore the expressions of pituitary tumor transforming gene and c-myc gene in patients with multiple myeloma (MM) and its relationship with pathogenesis of MM. Expressions of pituitary tumor transforming gene and c-myc gene mRNA in BMMNC from 33 patients with MM and 10 normal controls were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that the expressions of pituitary tumor transforming gene and c-myc gene mRNA were significantly higher in MM patients those that in normal controls (p<0.05). The expression of pituitary tumor transforming gene mRNA was significantly correlated with the expression of c-myc gene (r=0.801, p<0.05). In conclusion, the overexpressions of pituitary tumor transforming gene and c-myc gene may be related to the pathogenesis and progression of MM.