Objective To investigate the correlation and causal relationship between neonatal birth weight and urinary microproteins and creatinine in adulthood. Methods Genome-wide association studies were conducted to extract genetic loci with significant influence from dataset as instrumental variables，and they were analyzed by inverse variance weighted（IVW），weighted median，MR Egger，and MR-PRESSO methods to investigate the causal relationship between neonatal birth weight and urinary microproteins and creatinine in adulthood. A retrospective analysis was performed for 113 neonates who were admitted to Department of Neonatology，Shanxi Children’s Hospital，from January 2005 to January 2007，and related data were collected during the neonatal and adult stages. A Pearson correlation analysis was used to determine the correlation between neonatal birth weight and urinary microproteins and creatinine in adulthood. Results The MR-IVW test showed that neonatal birth weight had a statistically significant correlation with urinary microproteins（P=0.037） and urinary creatinine（P=0.015） in adulthood. The retrospective study showed that there were no significant differences between the two groups in all variables except body weight（P>0.05）. In addition，the Pearson correlation analysis showed that neonatal birth weight was negatively correlated with urinary microproteins（r=-0.78，P=0.015） and was positively correlated with urinary creatinine（r=0.78，P=0.018）. Conclusion Neonatal birth weight is negatively correlated with urinary microproteins and is positively correlated with urinary creatinine in adulthood.