OBJECTIVE To evaluate the association between PCSK9 predicted loss-of-function (pLoF) variants and glycemic traits, hepatobiliary function, and neurocognitive traits. RESEARCH DESIGN AND METHODS We identified carriers of PCSK9 pLoF variants in UK Biobank exome sequencing data. We assessed the aggregate effects of these variants on lipid and lipoprotein traits, which served as a positive control. Association of PCSK9 pLoF carrier status and glycemic traits, hepatobiliary function, and neurocognitive traits was then evaluated as a measure for adverse effects. RESULTS We identified 374 individuals carrying one of 41 unique PCSK9 pLoF variants. As expected, we found that PCSK9 pLoF carriers had significantly lower LDL cholesterol C levels (P 5 7.4 × 10²⁵⁵ ) and apolipoprotein B levels (P 5 7.6 × 10²⁵⁰ ) than did noncarriers. However, we found no significant associations between pLoF carrier status and glycemic traits, hepatobiliary function, and neurocognitive traits (P > 0.05). CONCLUSIONS Our results do not support adverse effects of PCSK9 pLoF variants on glycemic traits, hepatobiliary function, or neurocognitive traits.