Background: diabetic foot ulcers (DFU) represent the main cause of major amputations and hospitalisations in diabetic patients. The aim of this study was to assess the safety and cost-efficacy of intramuscular injection of peripheral blood mononuclear cells (PBMNCs) in diabetic patients with no-option chronic limb-threatening ischemia (CLTI) and small artery disease (SAD). Methods: a retrospective study was carried out on a series of type 2 diabetic patients with DFU grade Texas 3 and no-option CLTI and SAD. All patients had undergone at least a previous revascularization and were allocated to a surgery waiting list for major amputation. The principal endpoint evaluated at 90 days was a composite of TcPO2values at the first toe ≥30 mmHg and/or TcPO2increase of at least 50% from baseline and/or ulcer healing. Secondary endpoints were individual components of the primary endpoint, any serious and non-serious adverse events, and direct costs at one year. Results: the composite endpoint was achieved in nine patients (60.0%); one patient (6.7%) healed within ninety days and 26.7% and 46.7% showed TcPO2≥ 30 mmHg and a TcPO2increase of at least 50% at ninety days, respectively. At one year, three (20.0%) patients underwent a major amputation (all diagnosed SAD grade III). One patient died after seven months, and seven patients (46.7%) healed. The overall median and mean cost per patient were EUR 8238 ± 7798 and EUR 4426 (3798; 8262), respectively. Conclusions: the use of PBMNCs implants in no-option CLTI diabetic patients with SAD seems to be of help in reducing the risk of major amputation.