We examined the association of 34 single nucleotide polymorphisms with weight loss up to 9.5 years after Roux-en-Y surgery. Participants were enrollees in the NUgene biobank with stored DNA and linked electronic health records. Ninety-five self-identified white participants underwent surgery and had follow-up weights obtained between 1 and 9.5 years after surgery. SNP rs4771122 was the variant most significantly associated with long term weight loss after surgery in a repeated linear mixed model (p = .004) of long-term weight loss. In this model, each additional copy of the minor allele was associated with nearly 5 percent greater percentage weight loss. This same SNP was also nominally significantly (p