BACKGROUND: Platinum-etoposide (PE) chemotherapy (CH) is a globally established combination for extra-pulmonary high grade neuroendocrine carcinoma (EP-G3-NEC); the optimal schedule has not been established. METHODS: An international survey was designed, and completed by clinicians with an expertise in the field to assess consistency in clinical practice. RESULTS: Seventy-five replies were received (June-Nov'17). A minority of physicians (13; 17.6%) did not take Ki-67 or morphology (9; 12.0%) into consideration for selection of CH. Most (72; 96.0%) selected PE-CH as first-line treatment for EP-G3-NEC. CH schedules varied: cisplatin-based (37/71; 52.1%), carboplatin-based (34/71; 47.9%); intravenous etoposide (64/71; 90.1%), oral etoposide (7/71; 9.9%). Choice of second-line CH depended on time to progression on PE-based first-line: if?>?6 months, re-challenge with PE was the preferred choice (34; 45.9%); if?6 months, alternative combinations such as fluoropyrimidine/irinotecan (21; 29.2%) or temozolomide/capecitabine (22; 30.6%) were used. CONCLUSION: Significant variation in PE regimen employed exists. Standardising clinical practice would facilitate clinical trial development.