PURPOSE Assessment of cancer diagnostic and treatment capacity is crucial to optimizing cancer care, especially in the setting of limited resources, including as a result of war. We assessed personnel, equipment, and treatment availability during Russia's full-scale invasion of Ukraine to define gaps that could then be addressed with tailored strategies. METHODS An online survey designed in collaboration with oncology specialists from the National Cancer Institute in Ukraine was distributed to oncologists in Ukraine through oncology-related social media. Data were analysed using descriptive statistics. RESULTS 192 physicians from all regions of Ukraine, including 53 (23.6%) medical oncologists, 89 (46.4%) surgical oncologists, and 32 (16.7%) radiation oncologists completed the survey. The average number of medical oncologists per regional cancer centre was 4.7 compared to 2.5 seen as the optimal number. The average number of nurses trained in chemotherapy administration was 6.4 compared to the desired number of 8.6. The average number of chemotherapy infusion machines was 8.2 compared to 17.7 desired. On average, 5.7 ports were put in per month compared to 22.1 desired. Average number of infusion chairs was 6.4 compared to 16.3 desired, while the number of inpatient chemotherapy beds was 26.8 compared to 34.0 perceived as the optimal number. The reported average number of surgical oncologists was 12.1 with an optimal average of 6.0. The average number of surgical beds was 52.8 v 60.7 desired. The average and optimal numbers of the following were fairly close: surgical oncology trainees (2.1 v 2.6), operating room nurses (4.1 v 4.3), anesthesiologists (4.4 v 4.2), operating rooms (3.6 v 3.4), anaesthesia machines (4.4 v 4.0), average surgeries per week (21.5 v 21.8). The average number of radiation oncologists was 7.9 compared to 8.5 optimal numbers. For other metrics, average and optimal numbers were somewhat close: number of radiation therapy laboratory technicians (7.9 v 8.5), medical physicists (3.8 v 4.8), dosimetrists (1.5 v 2.1), Cobalt 60 machines (0.9 v 1.1), brachytherapy machines (1.1 v 1.7). CONCLUSION We identified important equipment and personnel gaps in oncology care in Ukraine. Results are limited by the decreased number of respondents from areas directly affected by active hostilities.