Abstract: ObjectiveTo evaluate the feasibility and efficacy of the intra-peritoneal chemotherapy guided by ATP biolu minescence tumor chemo-sensitivity assay for human colorectal cancer. Methods Thirty-two cases with the colorectal cancer malignant ascites were collected for ATP-TCA to deter mine the chemo-sensitivity. The drug with the highest inhibition rate was selected for intra-peritoneal chemotherapy. The results of ATP-TCA and the response of malignant ascites, the clinical features and Karnofsky performance score(KPS) were analyzed. ResultsThere were considerable differences in chemo-sensitivity between individuals. Hydroxycamptothecin(HCPT) was the most effective to the colorectal cancer malignant ascites. Fifteen patients showed response by intra-peritoneal chemotherapy (complete response: 1, partial response: 14). The KPS of the responders was improved significantly. ConclusionIn vitro chemo-sensitivity ATP biolu minescence tumor assay was safe and effective to guide intra-peritoneal chemotherapy for colorectal cancer malignant ascites, through improvement of the KPS.