Insulin-like growth factor-I (IGF-I) is a key hormone in the vertebrate growth axis. Thus, the identification of polymorphic IGF-I gene molecular markers could aid in selection for desirable growth traits. We identified two polymorphic microsatellite loci with tetrad repeats in the IGF-I gene by polymerase chain reaction (PCR) and sequencing in common carp (Cyprinus carpio). One locus in intron1 was designated intron1189, and the other locus in intron2 was designated intron2310. The allele and genotype information for the two loci were obtained by polyacrylamide gel electrophoresis for all individuals from Heilongjiang carp (Cyprinus cario haematopterus) (YL) (n=263), a selected line of German mirror carp (Cyprinus carpio L. mirror) (JL) (n=229), and a cold-resistant line of Hebao red carp (Cyprinus carpio var. wuyuanensis) (HL) (n=255). We evaluated the association between the genotypes that constituted >3 percent of the frequencies of the two loci and growth-related traits. The allele numbers were 15 (intron1189) and 25 (intron2310), and both loci were high polymorphic (PIC>0.5). The number of genotypes that exceeded 3% of the frequency were 12 and 9 (YL), 12 and 10 (JL), and 10 and 10 (HL), respectively. The polymorphism at the intron1189 locus was significantly correlated with body length at 135 and 325 d, and body weight at 325 and 385 d in YL (P<0.05). There was a significant correlation between the polymorphism of intron2310 locus and body length and body weight during each detection period in JL (P<0.05). Fish with genotype 185/229 at intron1189 had the lowest body length at 135 and 325 d and the lowest body weight at 325 and 385 d in YL. Conversely, fish with genotype 205/221 at intron1189 had the highest body length at 135 and 325 d and the highest body weight at 325 d in YL. At intron2310, JL individuals with genotype 290/350 had the lowest body length at all time points and the lowest body weight at 135, 325, and 385 d. In contrast, body length and body weight were highest at these time in JL individuals with genotype 318/350. In summary, we isolated two microsatellite loci that have high polymorphism from introns of the IGF-I gene. These markers appear to be correlated with growth performance and should be further investigated to develop marker assisted selection breeding programs in common carp.