Background: With extending life expectancy, more people are diagnosed with cutaneous malignancies at advanced ages and are offered nonsurgical treatment. We assessed outcomes of the oldest-old adults after electrochemotherapy (ECT). Methods: The International Network for Sharing Practices of ECT (InspECT) registry was queried for adults aged ≥90 years (ys) with skin cancers/cutaneous metastases of any histotype who underwent bleomycin-ECT (2006–2019). These were subanalysed with patients aged <90 ys after matching 1:2 for tumor location, number, size, histotype, and previous treatments. We assessed ECT modalities, toxicity (CTCAE), response (RECIST), and patient perception (EQ-5D). Results: Sixty-one patients represented the study cohort (median 92 ys, range 92–104), 122 the control group (median 77 ys, range 23–89). Among the oldest-old, 44 patients (72%) had primary/recurrent skin cancers, 17 (28%) cutaneous metastases. Median tumour size was 15 mm (range, 5–450). The oldest-old adults underwent ECT mainly under local/regional anaesthesia (59% vs 39% p =.012). We observed no differences regarding dose and route of chemotherapy (intravenous vs intratumoral, p =.308), electrode geometry (linear vs hexagonal, p =.172) and procedural duration (18 vs 21 min, p =.378). Complete response (57.4 [95%-CI 44.1%–70.0%] vs 64.7% [95%-CI 55.6%–73.2%], p =.222) and 1-year local control (76.7% vs 81.7, p =.092) rates were comparable. Pain and skin hyperpigmentation were mild in both groups. Skin ulceration persisted longer in the oldest-old patients (4.4 vs 2.4 months, p =.008). Conclusions: The oldest-old adults with cutaneous malignancies undergo ECT most commonly under local/regional anaesthesia with safety profiles and clinical effectiveness similar to their younger counterparts, except in case of ulcerated tumors.