Background/Aim: Total fat intake has an important impact on the low-density lipoprotein (LDL) peak particle diameter (LDL-PPD) and may interact with nutrient-sensitive single nucleotide polymorphisms (SNPs). The objective wasto examine whether there is suggestive evidence of SNP × dietary fat intake interaction effects influencing the LDL-PPD in the Quebec Family Study (QFS) in order to generate hypotheses to be tested in larger studies. Methods: SNPs from a genome-wide association study (GWAS) using Illumina Human610-Quad BeadChip, total fat intake derived from a 3-day weighted food record, and SNP × total fat intake interaction effects were examined on LDL-PPD in 541 QFS subjects. Results: The GWAS analyses 29 identified independent SNP × total fat intake interaction effects on the LDL-PPD at p < 10-5, including SNPs in the following genes: ABCG2, CPA3, FNBP1, KCNQ3, NBAS, NCALD, OPRL1, NKAIN2, SH3BGRL2, SOX5, and SUSD4. Conclusions: This observational study suggests that multiple SNPs interact with dietary fat intake to influence variation in the LDL-PPD.