Growth and fatness traits are complex and economically important traits in pig industry. The molecular basis underlying porcine growth and fatness traits remains largely unknown. Here we explored the GeneSeek GGP Porcine 80K SNP chip to perform a genome-wide association study for seven growth and fatness traits in 365 individuals from the Sujiang pig, a recently developed breed in China. We found considerable phenotypic variability within this population. The genomic heritability of the seven traits ranged from 0.33 to 0.62. We identified two, 17, one and 11 chromosome-wide significant (P < 1.87E-05, defined by the Bonferroni method) SNPs for body weight, chest circumference, chest width and backfat thickness, respectively. Of these SNPs, 20 represent novel genetic loci, and five and four SNPs were respectively associated with chest circumference and backfat thickness at a genome-wide significant threshold (P < 9.36E-07). Eight SNPs had pleiotropic effect on both chest circumference and backfat thickness. The most remarkable locus resided in a region between 79.41 Mb and 83.37 Mb on pig chromosome 4, harboring a number of previously reported quantitative trait loci related to backfat deposition. In addition to a known one (TAS2R38), we identified seven genes including APBA2, PRKDC, CEBPD, DPT, MPC2, CREG1 and MGAM as novel candidates for body weight and backfat thickness at the mapped loci. Our findings provide insights into the genetic architecture of porcine growth and fatness traits and potential markers for selective breeding of Chinese Sujiang pigs.