The aim of this study was to analyze the correlations between NAT1 and clinicopathological features of and prognosis in colorectal cancer (CRC). RNA sequencing data and clinical information were retrieved from The Cancer Genome Atlas database. Wilcoxon test, logistic regression and Kaplan–Meier method were used to estimate the association between NAT1 and prognosis in CRC. In vitro experiments were conducted to confirm the role of NAT1. NAT1 is significantly less expressed in CRC and independently associated with poor prognosis in CRC patients. The authors further confirmed that expression of NAT1 was significantly lower in SW116 colon cancer cells than in NCM460 cells. Overexpressed NAT1 obviously inhibited the growth of CRC cells by downregulating phosphorylation of the PI3K/Akt/mTOR signaling pathway. NAT1 may be a potential therapeutic target for CRC.