Introduction: Pet ownership is widespread, with many owners reporting emotional benefits, but evidence on its psychological and biological effects remains mixed. Prior research has linked strong pet attachment, particularly to dogs, to lower psychosocial distress, but underlying biological mechanisms are not well understood. We examined associations of pet ownership and attachment with a metabolite-based psychosocial distress score (MDS) and broader metabolic profiles, distinguishing between dogs and cats. Methods: We analyzed data from 213 participants (131 pet owners, 82 non-owners), using the Lexington Attachment to Pets Scale and a previously developed MDS reflecting psychosocial distress. Linear regression assessed associations between pet variables and MDS or individual metabolites, adjusting for demographic, lifestyle, and health factors. Metabolite set enrichment analysis identified associated metabolite classes. Results: Pet ownership and pet attachment were not associated with MDS overall. However, stronger pet attachment was associated with lower MDS ({beta}(95%CI)=-0.58(-1.07,-0.08), p=0.02) among dog owners but not cat owners. Across all measured metabolites, N6,N6-dimethyllysine was significantly associated with pet attachment. Several metabolite classes were associated with pet ownership and attachment, with some in opposite directions. For example, triglycerides with than three double bonds were positively associated with ownership but inversely with attachment, particularly among cat owners. Conclusion: Although pet ownership and attachment were not associated with MDS overall, stronger attachment was associated with lower MDS among dog owners but not cat owners. Pet ownership and attachment showed distinct metabolomic patterns, with differences between dog and cat owners. Further studies are needed to replicate and expand on these findings.