Twenty genes involved in fatty acid metabolism were studied to reveal their effects on chicken fatness traits. To explore the interactions among these genes and evaluate their effects on fat accumulation in chickens, a Bayesian network of candidate genes in fatty acid metabolism and growth was constructed in terms of these genes' mRNA expression data derived from DNA microarray and the effects of these genes on fatness traits were analyzed. A full-sib family Beijing-You chicken population was raised and sampled for investigating the hepatic mRNA expression and measuring the fatness traits at 5 time points from 42 to 98 d. By using a Bayesian network toolbox, we obtained a Bayesian-directed acyclic network, which has 19 nodes and 28 edges. The results showed that the heart-type fatty acid-binding protein (H-FABP) was the hub of the network with connection to 7 other genes. The hepatic mRNA expression of H-FABP was significantly related to i.m. fat content (r = -0.44, P < 0.05) at 70 d of age. The results indicated that the H-FABP gene plays the most important role among these genes associated with fatty acid metabolism and affects i.m. fat content of chickens.