Background: Autologous cell-therapy (ACT) is a new treatment method for patients with diabetes and no-option chronic limb-threatening ischemia (NO-CLTI). We aimed to assess the impact of ACT on CLTI in comparison with standard treatment (ST) in a randomized controlled trial. Methods: Forty diabetic patients with NO-CLTI were randomized to receive either cell therapy (n=20) or standard conservative therapy (n=16); 4 patients dropped out of the study. After 3 months, those in the ST group were switched to ACT (cell therapy crossover). The effect on ischemia and diabetic foot was assessed by changes in transcutaneous oxygen pressure (TcPO2) and the number of healed patients at 3 months. Amputation rates and amputation-free survival (AFS) were assessed at 3 months and then during 12-month follow-up. Results: TcPO2 increased significantly in the ACT group after 1 and 3 months (both p<0.001) whereas TcPO2 in the control group remained unchanged (NS). After the crossover to cell therapy in patients of the ST group, we observed a significant increase in TcPO2 at 1 and 3 months after the injection of ACT (p=0.036 and p<0.001, respectively). We also observed significantly more healed patients at 3 months in the ACT group compared to the ST group (p=0.01). The rates of major amputation and AFS at 3 months were not significantly different between the ACT and ST groups (both NS). In Kaplan-Meier estimate, patients treated initially by ACT showed a trend towards higher AFS rates compared to those treated initially by ST who received ACT after the 3-month delay, but without a significant difference (65 vs. 43.8%). Conclusions: Our study showed that ACT in patients with no-option CLTI and diabetic foot significantly improved limb ischemia and wound healing when compared to standard conservative therapy, without influencing amputation rates and with a trend to higher 1-year AFS in comparison with delayed ACT treatment in ST group. Disclosure M. Dubsky: None. R. Bem: None. A. Nemcova: None. J. Husáková: None. V. Fejfarova: None. A. Jirkovska: None. K. Sutoris: None. Funding Ministry of Health of the Czech Republic (16-27262A, 00023001)