During the winter season 2017, in a commercial nursery located in the area of Olmedo (Sassari, Italy), severe symptoms of stem rot were observed on Euphorbia pulcherrima. Rot symptoms originated from the collar and, as disease progressed, the entire stem collapsed and the plant wilted. The same symptoms reappeared in 2018, affecting approximately 10% of the potted plants. Stem sections from different plants were washed, surface-sterilized in 70% ethanol for 10 s, and rinsed twice in sterile water. Tissue fragments (2 × 2-mm) were transferred on potato dextrose agar (PDA) containing 100 mg/L each of oxytetracycline hydrochloride and streptomycin sulphate. Following incubation at 25 °C for 4–6 d, fungal colonies were subcultured on PDA and examined after 7–10 d. Morphological identification was based on monosporic cultures grown on carnation leaf agar (CLA) and Spezieller Nährstoffarmer Agar (SNA) for 14 d at 25 °C, 12 h photoperiod. Monosporic cultures produced oval to ellipsoid aseptate microconidia born from short monophialides, 0.3–11.2 × 1.8–4.8 μm, and 1- or 2-septate microconia 11.7-22 × 1.7–3.8 μm. The macroconidia were falcate to almost straight, usually with 3–4 septa, measuring 27.7–45.8 × 2.7–4.3 μm, with short slightly curved apical cell and a foot shaped basal cell. Based on morphology, isolates were provisionally identified as Fusarium oxysporum Schlecht. emend. Snyder and Hansen. DNA was extracted from three monosporic cultures, and part of the EF1-α gene was amplified with primers EF1/EF2 (O’Donnell et al. 1998). The amplicons (~700 bp; GenBank accession Nos. MN022422, MN022423, MN022424) were sequenced on both senses; sequences were blasted in the FUSARIUM-ID database and showed 100% homology with F. oxysporum species complex (isolate NRRL 39464). Pathogenicity of the three isolates was determined on 2-month-old potted plants of E. pulcherrima (cv. Christmas Beauty; 6 plants/strain) by wounding the collar with a sterile needle and pipetting 106 CFU conidial suspension onto the lesion. Control plants were treated with 1 ml sterile water. Pots were placed in a glasshouse (12 h photoperiod; 27 °C day; 20 °C night). Symptoms of stem rot were observed at 14 dpi and complete wilting occurred at 30 dpi. F. oxysporum was consistently reisolated from inoculated plants. Upon DNA extraction, amplification and sequencing of the EF1-α gene, identity of the isolates was confirmed. To our knowledge, this is the first report of F. oxysporum causing stem rot and wilt of E. pulcherrima in Italy. Previously, F. oxysporum has been reported to cause wilt on poinsettia only in Poland (Orlikowski et al. 2007).