Abstract: Objective: To investigate the predictive value of peripheral blood neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) on in-hospital mortality in patients with spontaneous circulation recovery after cardiac arrest. Methods: This retrospective single-center study included patients who recovered from cardiac arrest in and out of hospital from April 2012 to November 2018. The hospitalization time of ICU was longer than 24 hours. The patients were divided into survival group and death group according to the outcome of discharge. Neutrophil to lymphocyte ratio (NLR) is defined as absolute neutrophil count divided by absolute lymphocyte count in peripheral blood, and platelet to lymphocyte ratio (PLR) is defined as absolute platelet count divided by absolute lymphocyte count in peripheral blood. The differences of NLR and PLR in survival group and death group within 24 hours and 48-72 hours were analyzed and compared. The predictive value of NLR and PLR in 24 hours and 48-72 hours in critical medicine department was discussed by multivariate analysis and ROC curve..Results: A total of 30 patients were enrolled, including 19 males (63.33%) aged 65.90 + 16.22 years, 9 survivors (30.00%) and 21 fatalities (70.00%). The APACHE II score of hospitalized dead patients was significantly higher than that of survivors within 24 hours after admission to ICU (27.86 (+6.96) than that of survivors (12.67 (+4.90), P < 0.001). Within 24 hours of admission, there was no significant difference in NLR of hospitalized dead and surviving patients 9.89 (6.17-26.00) vs 11.14 (3.53-15.75), P=0.326. PLR of dead patients was significantly lower than that of surviving patients 152.22 (73.91-267.29) vs 278.89 (164.11-472.15), P=0.045. At 48-72 h, the NLR of dead patients was significantly higher than that of survivors 17.94 (9.02-21.63) vs 5.56 (3.78-8.80), P=0.014, while PLR 182.86 (118.83-255.69) vs 181.82 (68.33-320.50), P=0.647 had no significant difference. The NLR of 48-72 h in survival group was significantly lower than that of 24 h 5.56 (3.78-8.80) vs. 9.89 (6.17-26.00), P=0.027, and the PLR of 48-72 h was significantly lower than that of 24 h 182.86 (118.83-255.69) vs. 278.89 (164.11-472.15), P=0.055. No matter whether or not the death patients were excluded from the intensive medical department, the NLR of 48-72 h in death group had no significant change 17.94.02.- 21.63) vs. 11.14 (3.53-15.75), P = 0.104; 17.94 (9.02-21.63) vs. 13.11 (8.03-23.98), P = 0.635; 48-72 h PLR vs. 24 h had no significant change 181.82 (68.33-320.50) vs. 152.22 (73.91-267.29), P = 0.481; 181.82 (68.33-320.50) vs. 217.77 (132.47-350), P = 1910. Multivariate logistic regression analysis showed that NLR OR 1.471, 95% CI (1.032-2.096), P=0.033 was an independent risk factor for in-hospital mortality prediction. 48-72 h NLR AUC = 0.812, 95% CI (0.611-1.000), P = 0.015, truncation value (> 9.18) predicted mortality sensitivity 76.9%, specificity 88.9%Conclusion: The PLR of patients with cardiac arrest, cardiopulmonary resuscitation and spontaneous circulation recovery was significantly lower in the death group than in the survival group after 24 hours of ICU admission, while the NLR of the death group was significantly higher than that of the survival group after 48-72 hours of ICU admission. The NLR and PLR of survivors tended to decrease with time, whereas those of dead patients tended to decrease with time. ICU admission for 48-72h NLR can be used as an independent risk factor for predicting hospitalization mortality in patients with successful CPR