Pig breeds have significant differences in fat deposition and muscle development ability.However, the molecular mechanism behind these differences is still unknown. In this study, the expression pattes of three candidate genes, suppressor of cytokine signaling 3 (SOCS-3), obesity (ob) and insulin-like growth factor Ⅰ (IGF-Ⅰ), which are involved in adipose metabolism or muscle development, were analyzed.Total RNA was extracted from dorsal subcutaneous adipose tissue and longissi(m)us of 8-month-old Bamei and Largewhite pigs. Semiquantitative reverse transcription-polymerase chain reaction was used to determine the expression levels of the SOCS-3 and ob genes in adipose tissue, and SOCS-3 and IGF-Ⅰ genes in muscletissue. The results showed that in adipose tissue the expression level of SOCS-3 was significantly higher in Bamei (obese) pigs than that in Largewhite (lean) pigs (P＜0.01). However, in muscle tissue it was significantly lower in Bamei than that in Largewhite pigs (P＜0.01). Furthermore, the expression of SOCS-3 was positively correlated to that of ob in adipose tissue and that of IGF-Ⅰ in muscletissue. These findings suggest that the difference in SOCS-3 gene expression levels in adipose and muscle tissues, the relationship between SOCS-3 and ob in adipose tissue, and that between SOCS-3 and IGF-Ⅰ in muscle tissue, might contribute to the different fat deposition and muscle development ability between obese and lean pigs.